# Components:
→ Chocolate & Cocoa
01 - 3.5 oz bittersweet chocolate (60–70% cacao), chopped
02 - 1.75 oz milk chocolate, chopped
03 - 1.75 oz white chocolate, chopped
04 - 1/4 cup unsweetened cocoa powder
→ Sourdough & Wet Ingredients
05 - 1/2 cup sourdough starter (100% hydration, unfed or discard acceptable)
06 - 1/2 cup unsalted butter, cubed
07 - 2 large eggs
08 - 1 teaspoon vanilla extract
09 - 2 tablespoons strong brewed espresso or 1 tablespoon instant espresso powder dissolved in 2 tablespoons hot water
→ Dry Ingredients
10 - 3/4 cup granulated sugar
11 - 1/4 cup light brown sugar, packed
12 - 3/4 cup all-purpose flour
13 - 1/2 teaspoon fine sea salt
# Method:
01 - Preheat oven to 350°F. Line an 8x8-inch baking pan with parchment paper, allowing overhang on sides for easy removal.
02 - Combine bittersweet chocolate and butter in a heatproof bowl. Set bowl over a saucepan of gently simmering water (double boiler method), stirring constantly until completely smooth. Remove from heat and allow to cool slightly.
03 - Whisk both granulated and brown sugars into the melted chocolate mixture until fully combined. Add eggs one at a time, whisking thoroughly after each addition. Stir in vanilla extract and espresso.
04 - Fold sourdough starter into the chocolate mixture until fully incorporated.
05 - Sift together flour, cocoa powder, and salt. Gently fold dry ingredients into the wet mixture using a spatula until just combined, taking care not to overmix.
06 - Fold milk chocolate and white chocolate pieces into the batter.
07 - Pour batter into prepared pan and smooth the surface evenly with a spatula.
08 - Bake for 32 to 36 minutes, until the center is just set and a toothpick inserted into the center emerges with moist crumbs.
09 - Allow brownies to cool completely in the pan before lifting out using parchment overhang. Cut into 12 equal squares.