Sourdough Discard Brownies Peanut (Printable)

Fudgy chocolate brownies made moist with sourdough discard and finished with a creamy peanut butter swirl.

# Ingredient List:

→ 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 - In a microwave-safe bowl, melt butter and chocolate together in 30-second intervals, stirring until smooth. Allow to cool for 3 minutes.
03 - In a large mixing bowl, whisk together sourdough discard, sugar, eggs, and vanilla until well combined.
04 - Pour melted chocolate mixture into the wet ingredients and whisk until smooth.
05 - Sift flour, cocoa powder, and salt into the chocolate mixture. Mix gently with a spatula until just combined without overmixing.
06 - Pour batter into prepared pan and smooth the top surface evenly.
07 - In a small bowl, stir together peanut butter and powdered sugar if using. Drop spoonfuls of peanut butter mixture over batter. Use a skewer or knife to gently swirl peanut butter throughout.
08 - Bake for 28-32 minutes until center is just set and a toothpick inserted comes out with moist crumbs.
09 - Let brownies cool completely in pan before slicing into squares.

# Expert Advice:

01 -
  • They're impossibly fudgy because the sourdough discard keeps them moist long after baking, which I discovered completely by accident.
  • Using your discard means you're actually being resourceful instead of wasteful, which feels surprisingly good.
  • The peanut butter swirl creates pockets of salty richness that cut through the chocolate in the most satisfying way.
02 -
  • Overbaking is the enemy here—pull them out when the center still jiggles just slightly, because they'll firm up as they cool and you want them to stay fudgy.
  • The sourdough discard actually changes the brownie chemistry, making them stay moist longer and requiring slightly less baking time than a traditional brownie recipe.
03 -
  • Measure your sourdough discard by weight, not volume, because it can be dense or fluffy depending on how much gas is in it, and weight is the only reliable method.
  • Don't let your chocolate-butter mixture get too hot before adding eggs, or you'll end up with scrambled bits throughout your batter, which I learned the hard way my first attempt.
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