Sourdough Sugar Cookie Bars with Vanilla Buttercream

These Sourdough Sugar Cookie Bars have all the buttery flavor and soft, chewy texture of classic sugar cookies—without all the rolling, cutting, and decorating! They’re baked in one pan, topped with a smooth vanilla buttercream frosting, and are perfect for birthdays, holidays, or anytime you’re craving an easy homemade dessert.

If you have a little extra time, my classic Sourdough Sugar Cookies are always worth making, but these bars are my go-to when I want something simpler. You can even long-ferment the dough for up to 3 days for even more sourdough flavor, and if you’re looking for another cookie favorite, my Sourdough Brown Sugar Cookies are another must-try.

Quick Look: Sourdough Sugar Cookie Bars

Prep Time: 15 minutes
Cook Time: 20–25 minutes
Total Time: 1 hour 40 minutes
Servings: 12 cookie bars
Calories: ~ 267 kcal per bar (based on nutrition panel)
Cook Method: Baked
Flavor Profile: Soft, buttery, and chewy with hints of vanilla and almond, topped with a smooth, creamy vanilla buttercream frosting. Easy to customize for any celebration!
Difficulty: Easy — Simple pantry ingredients, baked in one pan, and no rolling or cutting required!

SUMMARIZE & SAVE THIS CONTENT ON

Why You’ll Love These Sourdough Sugar Cookie Bars

Soft and chewy, not cakey — These bars stay soft and have the perfect chewy texture from the center all the way to the edges. The cornstarch and extra egg yolk help keep them tender so you won’t end up with dry, cakey cookie bars. My Sourdough Blondies are another chewy dessert that’s always a hit.
Made with simple pantry ingredients — If you already keep sourdough discard in the fridge, there’s a good chance you have everything else on hand already, too. These Sourdough Granola Bars are another easy sourdough discard recipe made with everyday pantry ingredients.
Rich, buttery flavor — Butter gives these bars that classic sugar cookie flavor, while the vanilla and almond extracts add a little extra depth. My Sourdough Thumbprint Cookies start with a similar buttery cookie dough before they’re filled with jam.
Easy to decorate for any occasion — I finished these with pink buttercream and confetti sprinkles, but they’re easy to change for just about any celebration. Swap the frosting color, use your favorite sprinkles, or leave them plain if you prefer. My Sourdough Fruit Pizza is another recipe that’s easy to dress up for birthdays, holidays, and other special occasions.
Can be long-fermented — The dough can be covered and refrigerated for up to 3 days before baking, making it easy to fit around your schedule. That’s especially handy if you’re baking for a party or holiday and want to spread the work out. My Overnight Sourdough Recipes collection includes plenty of other recipes you can prep ahead, too.

Ingredients & Substitutions

* To find precise measurements, scroll to the bottom of this post to find the recipe card*

ingredients for making sourdough sugar cookie dough

Unsalted butter—You’ll want to use room-temperature butter. If you press the butter, it leaves a fingerprint, but it doesn’t leave your finger oily. Cold butter doesn’t cream as well.
Sugar—I wouldn’t recommend reducing the sugar. It helps keep the cookie bars chewy rather than cakey, while also giving them the right amount of sweetness. Granulated white sugar gives these bars the classic sugar cookie flavor and texture, but organic cane sugar works well too.
Eggs—Use room temperature eggs so they mix more easily into the batter. Since the sourdough discard adds extra moisture, I only use the egg yolks to help keep the dough balanced. If you forgot to take the eggs out ahead of time, place them in a bowl of warm water for about 5 minutes.
Vanilla Extract—I used a combination of vanilla and almond extracts. I love the subtle fruity, nutty notes the almond extract adds to these sourdough sugar cookie bars, but you can leave it out if you prefer.
Flour – I use all-purpose flour for these sourdough discard sugar cookie bars. I haven’t tested this recipe with bread flour or whole wheat flour yet, but if you give either one a try, I’d love to hear how it turns out.
Leaveners—A little baking powder and baking soda give these delicious sugar cookie bars a light lift without making them cakey.
Cornstarch—Adding some cornstarch keeps these sourdough cookie bars soft, more tender, and chewier.
Sourdough Discard—For sweet treats like these easy sugar cookie bars, I prefer to use fresh sourdough discard that’s no older than 1–2 days. It gives the bars a classic sugar cookie flavor, while older discard adds a more noticeable tang. You can also use the same amount (by weight) of active sourdough starter.

Vanilla Buttercream

Unsalted butter: Use softened butter for the creamiest, smoothest buttercream. If you’re using salted butter instead, leave out the pinch of salt.
Food color: I used 1 drop of red food coloring to create a soft pastel pink, but it’s completely optional. You can easily customize these sugar cookie bars for any holiday or celebration by changing the frosting color and using your favorite sprinkles.
Powdered sugar
Confetti Sprinkles – My kid’s favorite part! I used these sprinkles! I love how you can easily change them out to fit for any holiday or celebration.

How to Make Sourdough Sugar Cookie Bars

Preheat the oven to 350°F and line an 8×8-inch square pan with parchment paper. Set aside.

In a medium bowl, whisk together the flour, baking powder, baking soda, cornstarch, and salt.

creamed butter and sugar in a standing mixer

In the bowl of a stand mixer (or electric mixer), cream together the butter and sugar until light and fluffy.

On low speed, mix in the egg yolks one at a time, then add the sourdough starter discard (or active starter), vanilla extract, and almond extract until smooth.

Slowly add the dry ingredients to the wet ingredients until no streaks of flour remain.

pressed sugar cookie bars dough into the baking pan

Press the cookie dough into the prepared baking pan.

Bake the sourdough sugar cookie bars for 20–25 minutes. The bars are done when the edges are lightly golden brown and the center still has a slight jiggle.

Remove the bars from the oven and place the pan on a wire rack to cool completely.

In a stand mixer fitted with the paddle attachment, beat the softened butter on medium speed for 2 minutes. Add the powdered sugar, heavy cream, vanilla extract, salt, and food coloring. Mix on low until combined, then beat until light and fluffy.

sourdough sugar cookie bars decorate with frosting

Top the cooled cookie bars with the frosting and sprinkles. Slice and enjoy!

McKenna’s Helpful Tips

Don’t overbake. This will make the bars cakey and dry instead of thick and chewy. The bars will continue to bake as they cool in the pan.
Use wet fingers to press the dough into the pan. The dough is thick, and lightly wetting your fingers makes it much easier to spread into an even layer.
Wipe your knife clean between slices. It only takes a few seconds, but it gives you much cleaner-looking bars after the buttercream has been spread on top. It’s the same trick that gives me clean-cut Sourdough Brownies.
The bars will sink. Don’t worry. This is normal. They’ll be covered with buttercream frosting, so no one will ever know.

How to Store

Store the frosted sugar cookie bars in an airtight container at room temperature for up to 3 days. If your kitchen is especially warm, store them in the refrigerator for up to 5 days. Let the bars sit at room temperature for about 20–30 minutes before serving so the buttercream softens and the bars have their best texture.

For longer storage, freeze the unfrosted cookie bars for up to 3 months. Wrap them tightly in plastic wrap, then place them in a freezer-safe container or bag. Thaw at room temperature before frosting and serving.

Sourdough Sugar Cookie Bars FAQs

Can you long-ferment these homemade sourdough sugar cookie bars?

Yes, you can! Cover the cookie bar dough and refrigerate it for up to 3 days before baking. When you’re ready to bake, let the dough come to room temperature first, or bake it straight from the refrigerator and add a few extra minutes to the baking time.

Can I add sprinkles to the sourdough sugar cookie dough?

Yes. Fold 60–80 grams of jimmy-style sprinkles into the cookie dough after the dry ingredients have been mixed in. Give it a quick mix, then press the dough into the prepared pan as directed. Jimmy-style sprinkles hold their shape much better than nonpareils. If you’re putting together a holiday cookie tray or dessert platter, consider pairing these bars with Sourdough Peanut Butter & Jelly Sandwich Cookies for a fun variety of flavors and colors.

How do I know my sourdough sugar cookie bars are done?

The cookie bars are done when the edges are lightly golden brown and the center still has a slight jiggle. If a toothpick inserted into the center comes out clean, they’re already overbaked. I use the same visual cues when baking Sourdough Magic Chocolate Bars to keep them soft and gooey.

Can I double the recipe?

Yes! You can double this recipe if you’re serving a larger crowd. Simply double the ingredients and bake the cookie bars in a 9×13-inch baking pan.

More Sourdough Bars Recipes

Sourdough Apple Pie Bars with Salted Caramel

Sourdough Magic Chocolate Bars Recipe {Pure Delight!}

Easy Sourdough Lemon Bars (Discard Recipe)

Easy Sourdough Discard Banana Bars Recipe

If you tried this Sourdough Sugar Cookie Bars recipe or any other recipe on my blog, please leave a 🌟 star rating and let me know how it went in the📝 comments below. Thanks for visiting!