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These sugar cookie bars are thick, soft, and frosted with fluffy vanilla buttercream—everything you love about bakery sugar cookies, baked in one pan and sliced into neat squares. They are designed for beginner to intermediate bakers using a regular oven, a hand mixer or whisk, and a simple 9 × 13 inch (23 × 33 cm) metal pan, so you can get a gorgeous tray of bars on the first try without fancy tools. The secret is a cookie‑style dough (not cake batter) with melted butter, a little cornstarch, and just enough egg, so the bars stay soft for days instead of turning dry or cakey.​

Pro tip: Pull the bars from the oven when the edges are just turning golden and the center still looks pale and soft—slight underbaking is what keeps the texture bakery‑soft after they cool.​

Why this recipe works

Sugar cookie bars live in the space between a cookie and a blondie: thick enough to slice, but with a fine, tender crumb instead of a dense square. Using melted butter coats the flour more evenly and adds rich flavor while keeping the mixing simple—no long creaming step needed—so the dough presses easily into the pan.​

A small amount of cornstarch softens the structure and mimics the melt‑in‑the‑mouth texture of classic sugar cookies. Granulated sugar gives clean, sweet flavor and helps create that slightly chewy edge, while just enough baking powder lifts the bars without making them dome and collapse. One whole egg plus an extra yolk add moisture and richness without the extra water that would push the bars toward cake territory.​

Ingredients with weights and purpose

For the sugar cookie bars (9 × 13 inch / 23 × 33 cm pan)

• All‑purpose flour — 315 g — about 2 ½ cups
  Purpose: Main structure; enough protein for clean slices but still tender.​
• Cornstarch — 15 g — 2 tbsp
  Purpose: Softens crumb and keeps bars delicate instead of bready.​
• Baking powder — 4 g — 1 tsp
  Purpose: Gentle lift so bars don’t bake up dense or collapse.​
• Fine sea salt — 3 g — ½ tsp
  Purpose: Balances sweetness and sharpens vanilla flavor.​
• Unsalted butter, melted then cooled — 170 g — ¾ cup
  Purpose: Rich flavor, easy mixing, and soft texture.​
• Granulated sugar — 220 g — 1 cup
  Purpose: Sweetness, structure, and a light chew at the edges.​
• Large egg — 1 (about 50 g without shell)
  Purpose: Binds dough and adds moisture.​
• Egg yolk — 1 (about 18 g)
  Purpose: Extra richness and tenderness without extra water.​
• Vanilla extract — 8 g — 2 tsp
  Purpose: Main flavor; use pure vanilla for best result.​
• Almond extract (optional) — ½ tsp
  Purpose: Classic “bakery sugar cookie” note.​
• Rainbow sprinkles (optional) — 30–40 g — ¼ cup
  Purpose: For funfetti‑style bars.​

For the vanilla buttercream frosting

• Unsalted butter, room temperature — 170 g — ¾ cup
• Icing/confectioners’ sugar, sifted — 340 g — about 2 ¾–3 cups
• Heavy cream or milk — 30–45 ml — 2–3 tbsp
• Vanilla extract — 5 g — 1 tsp
• Fine sea salt — pinch
• Gel food coloring and sprinkles on top — optional

The frosting is a simple American buttercream: the butter gives body, icing sugar thickens and sweetens, and a splash of cream makes it fluffy and spreadable.​

Equipment

Required

• 9 × 13 inch (23 × 33 cm) metal baking pan
• Mixing bowls (1 large, 1 medium)
• Whisk, rubber spatula, and/or hand mixer
• Digital kitchen scale (highly recommended)
• Oven or OTG, preheated to ${175}^{\circ }\text{C}$175∘C (350°F)
• Parchment paper

Nice to have

• Offset spatula for smoothing dough and frosting
• Oven thermometer to verify temperature
• Instant‑read thermometer for doneness checks

Step‑by‑step instructions with visual cues

1. Prep pan and oven

• Line pan with parchment, leaving overhang on the long sides, and lightly grease.​
• Preheat oven to ${175}^{\circ }\text{C}$175∘C (350°F) with rack in the center.​
• Visual cue: Parchment sits flat in the corners so dough can spread evenly.​

2. Mix dry ingredients

• In a medium bowl whisk flour, cornstarch, baking powder, and salt until fully blended.​
• Visual cue: Dry mix looks uniform, slightly aerated, and free of visible clumps.

3. Combine wet ingredients

• In a large bowl whisk melted, cooled butter with sugar for about 1 minute until slightly lightened and thick.​
• Whisk in egg, yolk, vanilla, and almond extract until smooth and glossy.​
• Visual cue: Mixture is cohesive, no streaks of egg, and falls from the whisk in a thick ribbon.

4. Make the dough

• Add dry ingredients to wet in two additions, folding gently with a spatula until just combined.​
• Fold in sprinkles if using.​
• Visual cue: Dough is thick and soft, like classic sugar cookie dough; it holds shape but presses easily.

5. Press into pan

• Scrape dough into prepared pan; press into an even layer, pushing firmly into corners and smoothing the top.​
• Visual cue: Surface is mostly flat with no big ridges or hollows; thickness is even.

6. Bake

• Bake 18–24 minutes, rotating once halfway.​
• Start checking at 18 minutes: edges lightly golden and just pulling from pan; center looks set but pale.​
• Toothpick near center should come out with a few moist crumbs, not wet batter; if using a thermometer, aim for around $93\text{–}{96}^{\circ }\text{C}$93–96∘C (200–205°F).​
• Visual cue: Bars may puff slightly but deflate as they cool; don’t wait for deep browning or they’ll dry out.

7. Cool completely

• Cool in pan on a rack until completely room temperature, about 1–1 ½ hours.​
• Visual cue: Top feels firm but springy; pan no longer warm.

8. Make frosting

• Beat room‑temperature butter 2–3 minutes until pale and fluffy.​
• Gradually beat in sifted icing sugar on low, then medium, until smooth.​
• Add 2 tbsp cream/milk, vanilla, and salt; beat 1–2 minutes until light and spreadable, adjusting thickness with more sugar or cream as needed.​
• Tint with gel color if desired.

9. Frost and slice

• Lift cooled slab from pan using parchment and set on a board.​
• Spread frosting evenly and add sprinkles.​
• For sharp edges, chill 20–30 minutes, then slice into 24–32 bars with a sharp knife, wiping the blade between cuts.
• ​

Troubleshooting: quick fixes

• Dry or crumbly bars: Most often from overbaking or too much flour; pull when edges are just golden, and weigh flour instead of scooping.​
• Greasy or underdone center: Too much butter or too little bake time; measure by weight and bake until only moist crumbs remain on a toothpick.​
• Sinking in the middle: Too much baking powder or underbaking; stick to the listed amount and make sure the center looks set.​
• Tough, bready texture: Overmixing after adding flour; fold just until no dry streaks remain.​
• Runny frosting: Butter too warm or too much liquid; chill briefly and beat in more sifted icing sugar.​

Substitutions and variations

Egg‑free
Replace 1 egg + 1 yolk with 60 g (¼ cup) full‑fat yogurt or sour cream plus 30 g (2 tbsp) milk; bars will be slightly denser but still soft.​

Dairy‑free
Use a good dairy‑free baking “butter” in both dough and frosting and swap milk/cream for oat or soy milk; chill before slicing for cleaner cuts.​

Gluten‑free
Use a 1:1 gluten‑free baking blend (same weight as flour); dough may feel stickier, so smooth it with a damp spatula, and cool fully before slicing.​

Flavor ideas

• Lemon: 1–2 tbsp lemon zest in dough, 2–3 tsp lemon juice in frosting (reduce milk slightly).​
• Confetti: Fold extra sprinkles into dough and on top.​
• Almond: Increase almond extract to 1 tsp and top with sliced toasted almonds.​

Storage, make‑ahead, and freezing

• Room temperature: Keep frosted bars in an airtight container up to 2–3 days in a cool kitchen.​
• Fridge: Store up to 5–7 days, well covered; bring to room temp 20–30 minutes before serving for best texture.​
• Freezer (unfrosted): Wrap the cooled slab in plastic, then foil, and freeze up to 2–3 months; thaw wrapped at room temp, then frost.​
• Freezer (frosted): Chill, slice, freeze pieces on a tray, then wrap and store in containers up to 2 months; thaw overnight in the fridge.​

FAQs

Can I use oil instead of butter?
Yes, but use 150 g (⅔ cup) neutral oil instead of 170 g butter; flavor will be less buttery and the crumb a touch more uniform.​

How do I stop them from drying out?
Don’t overbake, weigh your flour, and store bars airtight once cooled; aim for moist crumbs on the skewer, not a dry clean pick.​

How can I halve the recipe?
Bake in an 8 × 8 inch (20 × 20 cm) pan and start checking for doneness a few minutes earlier, as the bars will be thicker.​

Can I bake these in an OTG or air fryer?
In an OTG, use the middle rack and the same temperature; check a bit early if heat is strong. For an air fryer, use a small metal pan, reduce to about ${160}^{\circ }\text{C}$160∘C (325°F), and check often—air fryers cook faster.

​Final thoughts

Sugar cookie bars are one of those bakes that quietly earn a permanent spot in your rotation: simple ingredients, minimal hands‑on time, and a soft, frosted result that feels special enough for birthdays, potlucks, or just a Tuesday treat. By treating the base like a cookie dough (not a cake batter), watching the edges for light golden color, and letting the bars cool completely before frosting, you lock in that plush, bakery‑style texture without any guesswork.

Sugar Cookie Bars Recipe (Soft, Frosted, Party‑Ready)

Course: DessertCuisine: AmericanDifficulty: Easy, Medium

Servings

20

servings

Prep time

20

minutes

Cooking time

20

minutes

Calories

300

kcal

Total time

2

hours 

Cooling time: 60–90 minutes

Thick, soft sugar cookie bars baked in a 9×13 inch pan, topped with fluffy vanilla buttercream and sprinkles. All the flavor of bakery sugar cookies, without rolling or cutting.

Ingredients

For the sugar cookie bars (9×13 inch / 23×33 cm pan)

• 315 g all‑purpose flour (about 2 ½ cups, spooned and leveled)

• 15 g cornstarch (2 tbsp)

• 4 g baking powder (1 tsp)

• 3 g fine sea salt (½ tsp)

• 170 g unsalted butter, melted then cooled (¾ cup)

• 220 g granulated sugar (1 cup)

• 1 large egg (about 50 g without shell)

• 1 large egg yolk (about 18 g)

• 8 g pure vanilla extract (2 tsp)

• ½ tsp almond extract (optional but recommended)

• 30–40 g rainbow sprinkles (about ¼ cup, optional, for funfetti look)

• For the vanilla buttercream frosting

• 170 g unsalted butter, room temperature (¾ cup)

• 340 g icing/confectioners’ sugar, sifted (about 2 ¾–3 cups)

• 30–45 ml heavy cream or milk (2–3 tbsp), plus more as needed

• 5 g pure vanilla extract (1 tsp)

• Pinch fine sea salt

• Gel food coloring (optional)

• Extra sprinkles for topping (about 30–50 g)

Directions

• Prep the pan and oven
  Line a 9×13 inch metal baking pan with parchment paper, leaving an overhang on the long sides to lift the bars out later.
  Lightly grease the parchment and any exposed sides of the pan.
  Preheat the oven to 175°C (350°F) with a rack in the center. Allow at least 15 minutes for the oven to fully preheat.
  Visual cue: Parchment should sit flat in the corners with no big folds, so the dough can press into an even layer.
• Mix the dry ingredients
  In a medium bowl, whisk together the flour, cornstarch, baking powder, and salt until completely combined and slightly aerated.
  Visual cue: The mixture looks uniform and light, with no visible clumps of cornstarch or baking powder.
• Combine the wet ingredients
  In a large mixing bowl, whisk the melted, cooled butter and granulated sugar together for about 1 minute until slightly lightened in color and thick.
  Add the egg, egg yolk, vanilla, and almond extract (if using).
  Whisk until the mixture is smooth, glossy, and well combined, 30–45 seconds more.
  Visual cue: The mixture should fall from the whisk in thick ribbons with no streaks of egg or greasy separation.
• Make the dough
  Add the dry ingredients to the wet ingredients in two additions.
  Use a rubber spatula to fold gently until just combined and no dry flour pockets remain.
  If using sprinkles, fold them in at the end.
  Visual cue: The dough is thick, soft, and holds its shape (like sugar cookie dough), but still presses easily with the spatula. It should not be pourable like cake batter.
• Press into the pan
  Scrape the dough into the prepared pan.
  Use your spatula or clean hands to press the dough into an even layer, pushing firmly into the corners.
  Smooth the top with an offset spatula or the back of a spoon.
  Visual cue: The surface looks smooth and level with no big ridges or dips; dough thickness is as even as possible from edge to edge.
• Bake
  Place the pan on the center rack and bake at 175°C (350°F) for 18–24 minutes.
  Rotate the pan once halfway through baking for even browning.
  Start checking at 18 minutes:
  Edges should be lightly golden and just starting to pull away from the sides.
  The center should look set but still pale.
  A toothpick inserted near the center should come out with a few moist crumbs, not wet batter.
  If using an instant‑read thermometer, the center should be around 93–96°C (200–205°F).
  Visual cue: The top may puff slightly but will settle as it cools. Do not wait for the entire surface to turn golden brown or the bars will end up dry.
• Cool completely
  Place the pan on a wire rack and let the bars cool completely in the pan, about 60–90 minutes, until the pan is at room temperature.
  Visual cue: The center feels firm yet softly springy when lightly pressed, and the frosting will no longer melt on contact.
  
• Make the frosting
  In a large bowl, beat the room‑temperature butter with a hand mixer on medium speed for 2–3 minutes, until pale and fluffy.
  Gradually add the sifted icing sugar, about ½ cup at a time, beating on low to incorporate, then on medium until smooth.
  Add 2 tbsp of cream or milk, the vanilla, and a pinch of salt.
  Beat for 1–2 minutes until light and spreadable.
  Adjust consistency:
  Too thick: add more cream/milk 1 tsp at a time.
  Too thin: beat in extra sifted icing sugar 1–2 tbsp at a time.
  Tint with gel food coloring if desired.
  Visual cue: Frosting should form soft peaks, hold gentle swirls, and spread easily without tearing the cooled bars.
• Frost and slice
  Use the parchment overhang to lift the cooled cookie slab out of the pan and onto a cutting board.
  Spread the frosting evenly over the top with an offset spatula, creating swirls or keeping it smooth as you like.
  Add sprinkles on top and gently press them so they stick.
  For the cleanest cuts, chill the frosted slab in the fridge for 20–30 minutes.
  Slice into 24–32 bars with a sharp knife, wiping the blade between cuts.

Notes

• Optional substitutions (quick reference)
  Egg‑free: Replace 1 egg + 1 yolk with 60 g (¼ cup) full‑fat yogurt or sour cream + 30 g (2 tbsp) milk. Texture will be a bit denser but still soft.
  Dairy‑free: Use dairy‑free baking “butter” in both dough and frosting and a neutral non‑dairy milk (oat or soy) in the frosting.
  Gluten‑free: Use an equal weight of 1:1 gluten‑free baking blend (with xanthan gum). Dough will be a bit stickier; cool fully before slicing.
• Storage
  Room temperature: 2–3 days in an airtight container in a cool kitchen.
  Refrigerator: 5–7 days, well covered. Bring to room temperature for 20–30 minutes before serving.
  Freezer – unfrosted: Wrap the cooled slab tightly in plastic, then foil. Freeze up to 2–3 months. Thaw wrapped at room temp, then frost.
  Freezer – frosted: Chill, slice, freeze bars in a single layer, then wrap individually and store up to 2 months. Thaw overnight in the fridge, then bring to room temp.
  
• Nutrition (estimate)
  For 1 bar out of 24, including frosting (will vary by brand and exact cut size):
  Calories: ~280 kcal
  Carbohydrates: ~35 g
  Fat: ~14 g
  Protein: ~3 g
  Saturated fat and sugar are both relatively high, as expected for a frosted dessert bar.
  These numbers are rough estimates only. For precise values, enter the exact ingredients and brands into your preferred nutrition calculator.