If you’re looking for a unique, irresistibly soft treat that uses up sourdough discard, these sourdough sugar cookie bars are the perfect answer. With a buttery, melt-in-your-mouth base and a creamy vanilla frosting topped with colorful sprinkles, these cookie bars strike the perfect balance between classic sweetness and a subtle tang from the sourdough starter.
Whether you’re baking for a special celebration, sharing a treat with loved ones, or just craving a sugar cookie with a twist, this recipe delivers all the nostalgic flavor and satisfying texture in a simple bar form that’s easy to make and serve.
Table of Contents
Why You’ll Love Sourdough Sugar Cookie Bars
These sourdough sugar cookie bars combine the best of both worlds—classic sugar cookies and the complexity of sourdough. They’re soft, chewy, slightly tangy, and covered in a luscious frosting that elevates each bite. Plus, they help reduce waste by putting your sourdough discard to delicious use.
With easy-to-find ingredients and a simple mixing method, this recipe is great for beginner bakers and sourdough veterans alike. The dough can also be made ahead and refrigerated, making it a flexible option for busy schedules.
Who This Recipe Is For
This recipe is ideal for:
- Home bakers with extra sourdough discard on hand
- Parents who want to bake a fun, colorful treat with their kids
- People who love sugar cookies but want an easier, quicker bar version
- Anyone who enjoys soft, thick, frosted cookie bars
If you love baked goods with a tender crumb and frosted top, these bars are sure to become a favorite.
Ingredients You’ll Need (with Exact Quantities)
For the Cookie Dough:
- 8 tablespoons (112 g) unsalted butter, softened
- 3/4 cup (150 g) granulated white sugar
- 1 large egg, room temperature
- 2 teaspoons (5 g) vanilla extract
- 1/4 cup (50 g) sourdough starter discard (room temperature)
- 2 cups (240 g) all-purpose flour
- 1/2 teaspoon fine sea salt
- 1/2 teaspoon baking powder
For the Frosting:
- 4 tablespoons (56 g) softened butter
- 1 cup powdered sugar
- 1/2 teaspoon vanilla extract
- 1 tablespoon heavy cream (as needed for consistency)
Toppings:
- Sprinkles of your choice
Ingredient Notes and Variations
- Sourdough discard: Adds flavor and moisture. You can use an active starter in a pinch.
- Butter: Use high-quality unsalted butter for the best flavor. Kerrygold is a great option.
- Flour substitutes: Bread flour can be used if necessary; it will result in a slightly chewier texture.
- Salt type: If using table salt, use a heaping 1/4 teaspoon. For flaky sea salt, use 3/4 teaspoon.
- Frosting: Adjust consistency by adding more cream or powdered sugar. You can add food coloring for festive occasions.
Kitchen Equipment You’ll Need
- Stand mixer or electric hand mixer
- Mixing bowls (medium and large)
- Measuring cups or digital kitchen scale
- 8×8 inch baking tin
- Parchment paper
- Spatula and offset spatula (for frosting)
- Wire cooling rack
Step-by-Step Preparation: How to Make Sourdough Sugar Cookie Bars
Step 1: Preheat the Oven
If you’re baking immediately, preheat your oven to 350°F (176°C). Line an 8×8 inch baking tin with parchment paper, leaving overhang for easy removal. Lightly grease with butter or spray.
Step 2: Cream Butter and Sugar
In a mixing bowl, cream together the softened butter and granulated sugar using a stand or hand mixer. Mix for 2–3 minutes until light and fluffy.
Step 3: Add Wet Ingredients
Add the egg, vanilla extract, and sourdough discard. Mix until smooth and fully combined. Scrape down the sides as needed.
Step 4: Mix Dry Ingredients
Add the flour, baking powder, and sea salt to the bowl. Mix until just combined—avoid overmixing to maintain a tender texture.
Step 5: Shape and Bake
Press the dough evenly into the prepared baking tin using floured hands. Bake for 15–18 minutes, or until a toothpick comes out clean and the top is just turning golden.
Step 6: Cool Completely
Remove from oven and let the bars cool completely in the tin on a wire rack. Do not frost until fully cooled to prevent melting.
Step 7: Make the Frosting
In a bowl, beat together softened butter, powdered sugar, and vanilla. If the frosting is too thick, slowly add heavy cream until you reach a smooth, spreadable consistency.
Step 8: Frost and Decorate
Spread the frosting evenly over the cooled cookie base using an offset spatula. Add your favorite sprinkles on top.
Step 9: Slice and Serve
Lift the cookie sheet from the tin using parchment paper. Slice into 9 large or 18 small squares. Enjoy!
Pro Tips for the Best Cookie Bars
- Use a kitchen scale for precise measurements for consistently perfect results.
- Don’t overbake: Take them out when just golden to keep the bars soft.
- Chill the dough: If prepping ahead, chill for up to 3 days to ferment and deepen the flavor.
- Decorate with seasonal sprinkles: Great for holidays or themed events.
Common Mistakes to Avoid
- Skipping the cooling step: Frosting warm bars will cause the frosting to melt.
- Overmixing the dough: Can lead to tough cookie bars.
- Mis-measuring flour: Too much can make the bars dry; spoon and level or use a scale.
- Using too much sourdough starter: Stick to the recommended 1/4 cup for best texture.
Serving Suggestions
These cookie bars pair perfectly with:
- A hot cup of coffee or tea
- A scoop of pumpkin whipped cottage cheese for a creamy snack combo
- A drizzle of melted white chocolate on top for a gourmet touch
Great for school lunches, bake sales, birthday parties, or even gifting!
Creative Presentation Ideas
- Cut into shapes with cookie cutters after baking and cooling.
- Use colored frosting for holidays or themed celebrations.
- Serve in cupcake liners for a party-ready presentation.
Flavor Variations and Add-Ins
- Add lemon zest to the dough or frosting for brightness.
- Fold in mini chocolate chips or dried cranberries.
- Flavor the frosting with almond extract for a twist.
- Sprinkle toasted coconut or crushed nuts on top.
How to Store and Reheat
- Store in an airtight container in the refrigerator for up to 5 days.
- Freeze: Place bars on a baking sheet and freeze for 1 hour. Then store in layers with parchment paper in a freezer-safe container for up to 1 month.
- Serve chilled or at room temperature. No reheating needed.
Make-Ahead Tips
- Make the dough and press it into the pan up to 3 days ahead and refrigerate.
- Bake and freeze the entire pan of bars (unfrosted) for future frosting and slicing.
- Make the frosting in advance and store in the fridge; re-whip before using.
Frequently Asked Questions About sourdough sugar cookie bars
Can I use active sourdough starter instead of discard?
Yes! The flavor might be slightly less tangy, but the texture will still be fantastic.
Can I double this recipe?
Absolutely. Use a 9×13 inch pan and extend baking time by 5–7 minutes.
Is there a dairy-free option?
Yes, use plant-based butter and dairy-free cream in the frosting.
Do these taste sour like traditional sourdough bread?
No, the sourdough adds depth, not sourness. It enhances the flavor without overpowering.
Final Thoughts: A Must-Try Treat with a Sourdough Twist
These sourdough sugar cookie bars are the ultimate easy-to-make dessert that combines sweet nostalgia with modern sourdough flavor. Soft, chewy, frosted, and full of personality, they’re a creative way to use up starter discard while treating yourself and your family to something special.
Whether you’re baking for a crowd or just looking to satisfy your sweet tooth, these bars deliver every time.
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Soft & Chewy Sourdough Sugar Cookie Bars with Frosting
- Total Time: 28 minutes
- Yield: 9 large or 18 small bars 1x
Description
These sourdough sugar cookie bars are soft, chewy, buttery, and lightly tangy—made with sourdough discard for extra moisture and flavor. Finished with a creamy vanilla frosting and sprinkles, they’re an easy crowd-pleasing dessert that bakes fast and slices into perfect squares.
Ingredients
Cookie Bars
- 8 tbsp (112 g) unsalted butter, softened
- 3/4 cup (150 g) granulated sugar
- 1 large egg, room temperature
- 2 tsp (5 g) vanilla extract
- 1/4 cup (50 g) sourdough starter discard, room temperature
- 2 cups (240 g) all-purpose flour
- 1/2 tsp fine sea salt
- 1/2 tsp baking powder
Vanilla Frosting
- 4 tbsp (56 g) butter, softened
- 1 cup powdered sugar
- 1/2 tsp vanilla extract
- 1 tbsp heavy cream, plus more as needed
Topping
- Sprinkles, to taste
Instructions
- Prep: Preheat oven to 350°F (176°C). Line an 8×8-inch pan with parchment (leave overhang). Lightly grease.
- Cream: Beat butter and sugar for 2–3 minutes until light and fluffy.
- Add wet: Mix in egg, vanilla, and sourdough discard until smooth. Scrape bowl as needed.
- Add dry: Add flour, baking powder, and salt. Mix just until combined (don’t overmix).
- Press: Press dough evenly into the prepared pan (lightly flour hands if sticky).
- Bake: Bake 15–18 minutes, until the top is just turning golden and a toothpick comes out clean.
- Cool: Cool completely in the pan on a rack before frosting.
- Frosting: Beat butter, powdered sugar, and vanilla. Add cream a little at a time until spreadable.
- Finish: Spread frosting over cooled bars, add sprinkles, lift out, and slice into 9 large or 18 small bars.
Notes
- Don’t overbake: Pull when barely golden to keep bars soft and chewy.
- Make-ahead: Press dough into the pan and refrigerate up to 3 days; bake when ready (may need 1–2 extra minutes).
- Frosting texture: If too thick, add a splash more cream; if too thin, add powdered sugar.
- Freezing: Freeze unfrosted bars up to 1 month; thaw and frost before serving.
- Flavor ideas: Add lemon zest, mini chocolate chips, or almond extract in the frosting.
- Prep Time: 10 minutes
- Cook Time: 18 minutes
- Category: Dessert
- Method: Baking
- Cuisine: American
Nutrition
- Serving Size: 1 bar
