Sourdough Discard Brownies Peanut (Print Version)

Moist, fudgy chocolate squares enriched with sourdough discard and swirled with creamy peanut butter.

# Components:

→ Chocolate & Butter

01 - 1/2 cup unsalted butter
02 - 1 cup semisweet chocolate chips or chopped chocolate

→ Wet Ingredients

03 - 1/2 cup sourdough discard (unfed)
04 - 1 cup granulated sugar
05 - 2 large eggs
06 - 1 teaspoon vanilla extract

→ Dry Ingredients

07 - 1/2 cup all-purpose flour
08 - 1/4 cup unsweetened cocoa powder
09 - 1/2 teaspoon fine sea salt

→ Swirl

10 - 1/3 cup creamy peanut butter
11 - 1 tablespoon powdered sugar (optional)

# Directions:

01 - Preheat oven to 350°F. Line an 8x8 inch square baking pan with parchment paper.
02 - Combine butter and chocolate chips in a microwave-safe bowl. Heat in 30-second intervals, stirring between each burst until fully melted and smooth. Allow to cool for 3 minutes.
03 - In a large mixing bowl, whisk together sourdough discard, granulated sugar, eggs, and vanilla extract until thoroughly blended.
04 - Pour the cooled chocolate mixture into the wet ingredient mixture. Whisk until completely smooth.
05 - Sift flour, cocoa powder, and salt directly into the chocolate mixture. Fold gently with a spatula until just combined. Avoid overmixing.
06 - Pour batter into the prepared pan. Smooth the surface with a spatula.
07 - Mix peanut butter with powdered sugar if desired until smooth. Drop spoonfuls of peanut butter mixture evenly over the batter. Using a skewer or knife, gently swirl the peanut butter throughout the brownie batter in a decorative pattern.
08 - Bake for 28 to 32 minutes until the center is just set. A toothpick inserted in the center should emerge with moist crumbs, not wet batter.
09 - Allow brownies to cool completely in the pan before cutting into squares. Cut into 16 equal pieces.

# Expert Advice:

01 -
  • Your sourdough starter finally has a redemption arc instead of becoming kitchen waste.
  • These brownies stay fudgy and moist for days thanks to the discard adding unexpected depth.
  • The peanut butter swirl feels fancy enough for company but takes zero decorating skills.
  • Easy enough for a weeknight craving but impressive enough to wrap up and gift.
02 -
  • The sourdough discard must be unfed (meaning you haven't fed it recently) because active starter with bubbles will make your brownies rise too much and become cakey rather than fudgy.
  • Do not overmix the dry ingredients into the wet mixture—this is where people accidentally turn brownies into chocolate cake, and the difference is just a handful of extra whisks.
  • Baking times vary wildly between ovens, so the first time you make these, peek at 25 minutes and take notes on your specific oven's behavior.
03 -
  • If your sourdough starter is very thick and stiff, thin it with a tablespoon of water before measuring so it incorporates evenly into the batter.
  • Keep an oven thermometer in your baking space because oven temps are often off by 10-15 degrees, and this matters for getting the fudgy center right.
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