Triple Chocolate Sourdough Brownies (Printable Version)

Fudgy squares blending bittersweet, milk chocolate, and cocoa with tangy sourdough for chewy texture.

# Ingredient List:

→ Chocolate & Cocoa

01 - 4 oz bittersweet chocolate, chopped
02 - 2 oz milk chocolate, chopped
03 - 1/4 cup unsweetened Dutch-process cocoa powder

→ Fats

04 - 1/2 cup unsalted butter, cubed

→ Sugar

05 - 1 cup granulated sugar
06 - 1/4 cup light brown sugar, packed

→ Sourdough & Liquids

07 - 1/2 cup sourdough discard, unfed
08 - 2 large eggs, room temperature
09 - 1 teaspoon pure vanilla extract

→ Dry Ingredients

10 - 2/3 cup all-purpose flour
11 - 1/2 teaspoon fine sea salt

→ Chocolate Mix-ins

12 - 1/3 cup semi-sweet chocolate chips or chunks

# Steps:

01 - Preheat oven to 350°F. Line an 8-inch square baking pan with parchment paper, allowing overhang for easy removal.
02 - In a heatproof bowl, combine bittersweet chocolate, milk chocolate, cocoa powder, and butter. Melt over simmering water or microwave in 30-second intervals, stirring until smooth. Cool slightly.
03 - In a large bowl, whisk together granulated sugar, brown sugar, eggs, and vanilla extract until pale and thick, approximately 2-3 minutes.
04 - Whisk sourdough discard into the chocolate mixture until fully incorporated.
05 - Add the chocolate mixture to the egg-sugar mixture and blend gently until combined.
06 - Sift flour and salt over the mixture. Fold in gently with a spatula until just combined; avoid overmixing.
07 - Gently fold in semi-sweet chocolate chips or chunks.
08 - Transfer batter into prepared pan and smooth the top surface evenly.
09 - Bake for 28-32 minutes until edges are set and center is slightly wobbly. Avoid overbaking to maintain chewy center.
10 - Cool completely in pan on a wire rack before removing and slicing into squares.

# Expert Advice:

01 -
  • The sourdough discard creates an impossibly chewy center that tastes like you've aged the chocolate itself.
  • Three types of chocolate mean every bite has complexity without tasting cloyingly sweet.
  • It's the perfect excuse to finally use up that sourdough starter instead of watching it languish in your fridge.
02 -
  • Overbaking is the enemy here—err on the side of underdone because carryover heat keeps cooking as they cool; I learned this the hard way with crispy, sad brownies.
  • The sourdough discard must be unfed and cold, not bubbly and active, or you'll end up with a strange yeasty flavor instead of subtle tang.
  • Chilling these for at least an hour before slicing creates an even chewier texture and cleaner cuts—impatience leads to ragged edges.
03 -
  • Melting chocolate over water is gentler than microwave if you're nervous, but if you use the microwave, do 30-second bursts and stir between each one to prevent seizing.
  • Always weigh your ingredients rather than measuring by volume—flour especially can vary by 20 percent depending on how you scoop, which changes the texture entirely.
  • Sourdough discard straight from an unfed starter has just the right amount of active culture; fed starter or overly bubbly discard will make these taste yeasty and odd.
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