Sourdough Cosmic Chocolate Brownies (Printable)
Fudgy sourdough chocolate brownies with a tangy note and playful rainbow sprinkles.
# What You’ll Need:
→ Wet Ingredients
01 - 1/2 cup unsalted butter, melted
02 - 7 oz dark chocolate (70% cacao), chopped
03 - 3/4 cup granulated sugar
04 - 1/4 cup packed light brown sugar
05 - 2 large eggs, room temperature
06 - 1 tsp pure vanilla extract
07 - 1/2 cup active sourdough starter (unfed or discard works)
→ Dry Ingredients
08 - 2/3 cup 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
# Directions:
01 - Preheat the oven to 350°F. Line an 8x8-inch baking pan with parchment paper, leaving an overhang on two sides for easy removal.
02 - Combine the butter and chopped dark chocolate in a heatproof bowl. Set over a pot of barely simmering water (double boiler) and stir gently until completely smooth. Alternatively, melt in the microwave in 30-second bursts, stirring between intervals. Let cool for 5 minutes.
03 - Add the granulated sugar and brown sugar to the chocolate mixture, whisking vigorously until glossy and well blended. Beat in the eggs one at a time, making sure each is fully incorporated before adding the next. Stir in the vanilla extract.
04 - Gently fold the sourdough starter into the batter using a spatula, blending until no streaks remain. The starter adds a subtle tang and extra moisture.
05 - Sift the flour, cocoa powder, and sea salt directly into the bowl. Fold the dry ingredients into the wet batter with a spatula, mixing only until no dry pockets are visible. Overmixing will produce a tougher texture.
06 - Pour the batter into the prepared baking pan and spread it into an even layer. Scatter the mini chocolate chips or candy-coated pieces across the surface, then finish with a generous shower of rainbow sprinkles.
07 - Bake on the center rack for 28 to 32 minutes. Test doneness by inserting a toothpick into the center—it should come out with a few moist crumbs clinging to it, not wet batter.
08 - Transfer the pan to a wire cooling rack and let the brownies cool completely in the pan. Once fully set, use the parchment overhang to lift the slab out and cut into 16 squares.
# Expert Suggestions:
01 -
- The sourdough tang cuts through all that richness in a way that keeps you reaching for another square without feeling overwhelmed.
- Those rainbow sprinkles on top are not just cute, they turn an ordinary Tuesday into something worth noticing.
02 -
- I once pulled these out five minutes too late and the edges turned cakey, so trust me when I say bake closer to the minimum time for that dense fudgy center everyone fights over.
- If you do not have sourdough starter, 100 g of plain Greek yogurt works as a substitute and gives a similar gentle tang that makes people ask what your secret is.
03 -
- The batter should look thick and slightly resistant when you spread it into the pan, and if it seems too runny you may have overmixed, but it will still bake up delicious so do not panic.
- Use a serrated knife and cut straight down without sawing if you want those clean bakery style edges that make people think you bought them instead of baked them.