for 24 brownies
- 290g unsalted butter, plus more, softened, for greasing
- 225g good-quality milk chocolate, roughly chopped
- ¾ cup unsweetened dutch process cocoa powder, divided
- 1 tablespoon espresso/coffee powder
- 2 cups caster sugar (400 g)
- ½ cup dark brown sugar(110 g), packed
- 2 teaspoons vanilla extract
- 2 teaspoons salt
- 6 large eggs
- 1 cup all-purpose flour(125 g)
- flaky sea salt, for sprinkling
- Grease a 23×33-cm metal pan with softened butter, then line with parchment paper, leaving overhang on all sides.
- Combine the chopped chocolate, ¼ cup of cocoa powder, and espresso powder in a heatproof liquid measuring cup or medium bowl and set aside.
- Add the butter to a small saucepan over medium heat and cook until the butter just comes to a vigorous simmer, about 5 minutes, swirling the pan occasionally. Immediately pour the hot butter over the chocolate mixture and let sit for 2 minutes. Whisk until the chocolate is completely smooth and melted, then set aside.
- Combine the caster sugar, brown sugar, vanilla extract, salt, and eggs in a large bowl. Beat with an electric hand mixer on high speed until light and fluffy, about 10 minutes. It will be similar to the texture of very thick pancake batter.
- With the mixer on, pour in the slightly cooled chocolate and butter mixture and blend until smooth.
- Position a rack in the middle of the oven and preheat to 180°C
- Add in the flour and remaining cocoa powder and use a rubber spatula to gently fold until just combined.
- Pour the batter into the prepared baking pan and smooth the top with a spatula. Bake until lightly puffed on top, about 20 minutes.
- Remove the baking pan from the oven using oven mitts or kitchen towels, then lightly drop the pan on a flat surface 3-4 times until the brownies deflate slightly. Sprinkle with flaky sea salt.
- Return the pan to the oven and bake until a wooden skewer inserted into the center of the brownies comes out fudgy but the edges look cooked through, about 15 minutes more. The center of the brownies will seem under-baked, but the brownies will continue to set as they cool.
- Set the brownies on a cooling rack and cool completely in the pan.