Sourdough Cosmic Chocolate Brownies (Print version)

Tangy sourdough deepens fudgy chocolate brownies finished with mini chips and rainbow sprinkles for a playful crunch.

# What goes in:

→ Wet Ingredients

01 - 1/2 cup unsalted butter, melted
02 - 7 oz dark chocolate, chopped
03 - 3/4 cup granulated sugar
04 - 1/4 cup plus 2 tbsp light brown sugar
05 - 2 large eggs
06 - 1 tsp pure vanilla extract
07 - 1/2 cup active sourdough starter (100% hydration, unfed or discard)

→ Dry Ingredients

08 - 1/3 cup plus 2 tbsp all-purpose flour
09 - 1/4 cup unsweetened cocoa powder
10 - 1/2 tsp fine sea salt

→ Cosmic Topping

11 - 3/4 cup mini chocolate chips or candy-coated chocolate pieces
12 - 3 tbsp rainbow sprinkles

# Cooking steps:

01 - Preheat oven to 350°F. Line an 8x8 inch baking pan with parchment paper, leaving an overhang on two sides for easy removal.
02 - In a heatproof bowl set over a saucepan of simmering water, melt the butter and dark chocolate together, stirring occasionally. Alternatively, microwave in 30-second intervals, stirring between each. Let cool slightly until warm but not hot.
03 - Whisk the granulated sugar and brown sugar into the melted chocolate mixture until glossy and smooth. Add the eggs one at a time, whisking thoroughly after each addition. Stir in the vanilla extract.
04 - Fold the sourdough starter into the batter using a spatula, mixing until fully incorporated with no visible streaks.
05 - Sift the flour, cocoa powder, and salt directly into the wet mixture. Gently fold everything together with a spatula until just combined. Be careful not to overmix, as this will affect the fudgy texture.
06 - Pour the batter into the prepared baking pan and spread it into an even layer. Scatter the mini chocolate chips or candy pieces over the surface, followed by an even layer of rainbow sprinkles.
07 - Bake on the center rack for 28 to 32 minutes, or until a toothpick inserted into the center comes out with moist crumbs clinging to it. For a fudgier result, lean toward the shorter bake time.
08 - Allow the brownies to cool completely in the pan on a wire rack. Once fully set, use the parchment overhang to lift the slab out and cut into 16 even squares.

# Tips from flavorandfeast:

01 -
  • The sourdough starter adds a subtle tang that makes the chocolate taste deeper and more complex without anyone guessing your secret ingredient.
  • That fudgy, barely held together center is honestly better than any bakery brownie I have ever spent too much money on.
02 -
  • Underbaking slightly is always better than overbaking because the center firms up as it cools and nobody wants a dry brownie.
  • If your sourdough starter is very liquidy, reduce it by 10 grams or expect a slightly longer bake time to compensate for the extra moisture.
03 -
  • Use parchment overhangs as handles to lift the entire slab out before cutting so you get perfectly neat edges on every single brownie.
  • If you do not have sourdough starter, substitute 100 grams of plain Greek yogurt and add an extra tablespoon of flour for a similar tang and moisture balance.

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