Sourdough Cosmic Chocolate Brownies (Printable)
Fudgy sourdough chocolate brownies with tangy discard, glossy crust, and colorful cosmic sprinkles—baked in a 9-inch pan.
# What You’ll Need:
→ Wet Ingredients
01 - 1/2 cup unsalted butter, melted
02 - 7 oz dark chocolate, chopped
03 - 3/4 cup granulated sugar
04 - 1/3 cup packed light brown sugar
05 - 1/3 cup plus 1 1/2 tablespoons sourdough starter discard (unfed, room temperature)
06 - 2 large eggs
07 - 1 teaspoon vanilla extract
→ Dry Ingredients
08 - 1/3 cup plus 2 tablespoons all-purpose flour
09 - 1/4 cup unsweetened cocoa powder
10 - 1/2 teaspoon salt
→ Topping
11 - 1/4 cup plus 1 1/2 tablespoons mini chocolate chips
12 - 2 tablespoons colorful sprinkles (rainbow or cosmic style)
# Directions:
01 - Preheat oven to 350°F. Line a 9-inch square baking pan with parchment paper, leaving overhang on two sides for easy removal.
02 - In a microwave-safe bowl, melt the butter and chopped dark chocolate together in 30-second intervals, stirring between each burst until completely smooth. Set aside to cool slightly for about 5 minutes.
03 - In a large mixing bowl, whisk together the granulated sugar, light brown sugar, and eggs vigorously for about 2 minutes until the mixture becomes thick, pale, and glossy.
04 - Add the vanilla extract and sourdough discard to the egg-sugar mixture. Stir thoroughly until fully combined and no streaks of discard remain.
05 - Pour the melted chocolate mixture into the wet batter and fold gently until evenly incorporated throughout.
06 - In a separate bowl, sift together the all-purpose flour, cocoa powder, and salt. Gradually fold the dry ingredients into the wet batter using a spatula, mixing just until no flour pockets remain. Be careful not to overmix.
07 - Pour the batter into the prepared pan and spread it into an even layer. Scatter the mini chocolate chips and cosmic sprinkles uniformly across the surface.
08 - Bake for 28 to 32 minutes, or until the center is just set and a toothpick inserted into the middle comes out with moist crumbs clinging to it. Avoid overbaking for the best fudgy texture.
09 - Let the brownies cool in the pan for at least 20 minutes. Use the parchment overhang to lift them out, then slice into 16 even squares.
# Expert Tips:
01 -
- The sourdough discard adds a subtle tanginess that makes the chocolate taste richer without anyone guessing your secret ingredient.
- That cosmic sprinkle topping turns a humble pan of brownies into something that gets photographed before it gets eaten.
02 -
- Underbaking slightly is always better than overbaking because the brownies continue to set as they cool in the pan.
- Sourdough discard that has been sitting in the fridge for a week works beautifully, but if it smells sharply of acetone or nail polish remover, toss it and start fresh.
03 -
- Weigh your ingredients with a kitchen scale rather than using measuring cups because even a small excess of flour turns a fudgy brownie into a dry one.
- Let the melted chocolate cool until it is just warm to the touch before combining it with the eggs so you do not scramble them.