Ingredients:

  • 3/4 cup (170g) unsalted butter, melted and hot
  • 3/4 cup (75g) Dutch-process cocoa powder
  • 1 tsp (2g) espresso powder
  • 1 cup (200g) granulated sugar
  • 1/2 cup (110g) light brown sugar, packed
  • 3 large eggs, room temperature
  • 1 tbsp (13g) vanilla extract
  • 3/4 cup (95g) all-purpose flour, spooned and leveled
  • 1/2 tsp (3g) sea salt
  • 1/2 cup (90g) semi-sweet chocolate chunks

Instructions:

  1. Preheat your oven to 350°F (175°C). Line an 8x8 inch metal baking pan with parchment paper, leaving an overhang on the sides.
  2. Melt the 3/4 cup unsalted butter in a microwave safe bowl or small saucepan until it is bubbling hot. Immediately whisk in the 3/4 cup Dutch process cocoa powder and 1 tsp espresso powder until the mixture is smooth and glossy.
  3. Add the 1 cup granulated sugar and 1/2 cup packed light brown sugar to the chocolate mixture. Whisk vigorously for about 30 seconds until the sugar begins to dissolve into the fat.
  4. Add the 3 large eggs and 1 tbsp vanilla extract. Use a hand whisk to beat the mixture for 2 full minutes until the batter becomes thick, pale, and slightly ribbony.
  5. Add the 3/4 cup all purpose flour and 1/2 tsp sea salt. Switch to a spatula and fold the dry ingredients in by hand until just a few streaks of white remain visible.
  6. Toss in the 1/2 cup semi sweet chocolate chunks. Fold them in with 2 or 3 quick strokes until they are evenly distributed through the thick batter.
  7. Pour the batter into your prepared 8x8 inch pan and smooth the top. Bake at 350°F for 25 minutes until the edges are set but the center still has a slight wobble.
  8. Insert a toothpick into the center; it should come out with a few moist crumbs attached, not clean and not liquid. Note: If it's clean, they are overbaked.
  9. Place the pan on a wire rack and let it cool completely for at least 30 minutes until the structure has set and the center is firm.