These Sourdough Sugar Cookie Bar Hearts are the kind of dessert that feel extra special without requiring extra effort. Soft, buttery, and perfectly sweet, they’re made with sourdough discard for depth of flavor and baked into thick, tender bars that cut beautifully into heart shapes. Whether you’re baking for Valentine’s Day, a birthday, or just because, this recipe is simple, reliable, and made to be shared.

If you love these you’ve got to try my Sourdough Sugar Cookie Bars (soft & chewy!)

Table of Contents


sugar cookie bar hearts
  • Depth of flavor: The sourdough starter adds a subtle tang that makes the flavor more complex and irresistible.
  • Crowd pleaser: A fun, easy way to use up sourdough discard in a crowd-pleasing dessert.
  • Convenience: Stay moist and tender for days, making them great for make-ahead treats.
inside of sugar cookie bar

Tips for Success

  • Room Temperature Ingredients: Use room temperature ingredients to ensure even mixing and a smooth batter.
  • Measure Accurately: Weigh your ingredients for precise measurements, especially the flour and sugar, to achieve the desired consistency.
  • Sourdough discard: I recommend using discard no more than a week old as this may result in a sour result.
sugar cookie bar hearts

Helpful tools

Having the right tools on hand makes this recipe simple and stress-free. Below are a few helpful items to have before baking—linked for convenience if you’re in the market for them.

I was really happy with how this powder worked!
INGREDIENTS
  • 113 grams unsalted butter (softened)
  • 150 grams of sugar
  • 1 large egg
  • 100 grams of sourdough discard (fed or unfed & brought to room temp)
  • 7 grams vanilla extract
  • 140 grams of all-purpose flour
  • 3 grams of baking powder
  • 2 grams of salt
  • 3 grams (1 teaspoon) cornstarch
  • 80 grams of Valentine’s day sprinkles + more for topping

For the frosting:

  • 28 grams of unsalted butter (softened)
  • 170-180 grams powdered sugar
  • 30-45 grams of heavy cream
  • 5 grams vanilla extract
  • 1 drop of red food dye or natural coloring (for pink color-optional)
  • a pinch of salt to cut the sweetness (optional)
Equipment

Instructions

  • Preheat the oven to 350°F (175°C). Line a 9×9 inch (or 8×8-inch) baking pan with parchment paper.
  • Cream the butter and sugar together in a large bowl until light and fluffy (about 2–3 minutes). You can use a hand mixer or stand mixer for this step.
  • Add the egg, sourdough starter, and vanilla extract to the bowl. Mix until well combined and smooth.
mixing sugar cookie bar dough
mixing sugar cookie bar dough
  • In a separate bowl, whisk together the flour, baking powder, salt, and cornstarch.
  • Gradually mix the dry ingredients into the wet mixture, stirring just until combined. Be careful not to overmix.
  • Fold in the sprinkles using a spatula, making sure they’re evenly distributed throughout the dough.
mixing sugar cookie hearts
sugar cookie bar dough hearts
spreading sugar cookie bar dough
sugar cookie bar dough spread
  • Let the bars cool completely in the pan before shaping & frosting.
baked sourdough sugar cookie bars

How to make the frosting

  • In a medium bowl, beat the softened butter until smooth.
  • Add the powdered sugar, 2 tablespoons of heavy cream, vanilla extract, 1 drop of red food dye or natural dye, and a pinch of salt (if using). Beat until smooth and fluffy. Add the remaining tablespoon of cream if needed to reach your desired consistency.
  • Set frosting aside to prepare for shaping.
sugar cookie bar frosting
shaping sugar cookie bar hearts
shaped cookie bars
  • After shaping, frost each heart generously and finish with festive sprinkles or decorative toppings.
decorating sugar cookie bars
decorated sugar cookie bars
  • Store the frosted bars in an airtight container at room temperature for up to 2 days, or refrigerate for up to 5 days for maximum freshness.
sourdough sugar cookie bars hearts
sugar cookie bar crumb

More sourdough Valentine’s recipes

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sugar cookie bar hearts
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Sourdough Sugar Cookie Bar Hearts (soft & chewy!)

Soft, buttery sourdough sugar cookie bars cut into heart shapes and topped with frosting and sprinkles, an easy, festive dessert perfect for Valentine’s Day and sourdough discard baking.

Prep Time 30 mins
Cook Time 35 mins
1 hr 5 mins
Course: Dessert, Side Dish
Cuisine: American
Keyword: sourdough sugar cookie bar hearts
Servings: servings

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Equipment

  • 1 9x9 inch baking pan
  • Parchment paper
  • Food scale
  • Mixing bowl
  • Hand or stand mixer

Ingredients

  • 113 grams unsalted butter (softened )
  • 150 grams sugar
  • 1 large egg
  • 100 grams sourdough discard (fed or unfed & brought to room temp)
  • 7 grams vanilla extract
  • 140 grams all-purpose flour
  • 3 grams baking powder
  • 2 grams salt
  • 3 grams cornstarch
  • 80 grams Valentine's themed sprinkles (+ more for topping)

For the frosting

  • 28 grams unsalted butter (softened )
  • 170-180 grams powdered sugar
  • 30-45 grams heavy cream (start with 30)
  • 5 grams vanilla extract
  • 1-2 drops red natural or regular food dye (for pink color-optional )
  • a pinch of salt to cut the sweetness

Instructions

  1. Preheat the oven to 350°F (175°C). Line a 9×9 inch (or 8×8-inch) baking pan with parchment paper.
  2. Cream the butter and sugar together in a large bowl until light and fluffy (about 2–3 minutes). You can use a hand mixer or stand mixer for this step.
  3. Add the egg, sourdough starter, and vanilla extract to the bowl. Mix until well combined and smooth.
  4. In a separate bowl, whisk together the flour, baking powder, salt, and cornstarch.
  5. Gradually mix the dry ingredients into the wet mixture, stirring just until combined. Be careful not to overmix.
  6. Fold in the sprinkles using a spatula, making sure they’re evenly distributed throughout the dough.
  7. Spread the dough evenly into the prepared baking pan. Use a spatula or an icing tool to spread it into the corners and smooth the top. Note: this is a wetter sugar cookie bar dough, this is normal. It helps achieve optimal texture.
  8. Bake for 28-35 minutes, or until the edges are lightly golden and a toothpick inserted into the center comes out clean. Note: if using an 8×8 inch pan you may need to bake the sugar cookie bars a little longer.
  9. Let the bars cool completely in the pan before shaping & frosting.

How to make the frosting

  1. In a medium bowl, beat the softened butter until smooth.
  2. Add the powdered sugar, 2 tablespoons of heavy cream, vanilla extract, 1 drop of red food dye or natural dye, and a pinch of salt (if using). Beat until smooth and fluffy. Add the remaining tablespoon of cream if needed to reach your desired consistency.
  3. Set frosting aside to prepare for shaping.

How to Shape the Sugar Cookie Bar Hearts

  1. Once the cookie bars are fully baked, allow them to cool completely. This step is important, cutting while warm can cause the bars to crumble or lose their shape.
  2. Use a heart-shaped cookie cutter to cut out the cookies. You should be able to get about 9 heart shapes from one batch, depending on the size of your cutter. Press straight down for clean edges, and gently lift each heart out of the pan.
  3. After shaping, frost each heart generously and finish with festive sprinkles or decorative toppings.
  4. Store the frosted bars in an airtight container at room temperature for up to 2 days, or refrigerate for up to 5 days for maximum freshness.

Notes

Sourdough discard: Ensure your sourdough discard is no more than a week old to avoid a sour taste in the sugar cookie bars. Active starter can be used. 

Baking pan: If using an 8x8 inch baking pan the cookie bars may need to bake slightly longer. 

sugar cookie bar hearts