Slamming-Rich Sheet Brownies

1. 1

   Preheat the oven to 350 degrees. Line the bottom and sides of a 10-by-15-inch baking pan with aluminum foil, shiny side up. Lightly butter the foil.

2. 2

   Spread the walnuts on a rimmed baking sheet and bake until lightly toasted and fragrant, 8-10 minutes. Pour onto a plate to cool and then chop coarsely. Leave the oven on.

3. 3

   Place the chocolate and butter in the top pan of a double boiler and set over (but not touching) barely simmering water in the bottom pan. As they melt, stir occasionally with a wooden spoon. When fully melted, stir to blend and then remove from the heat and let cool slightly.

4. 4

   In a bowl, stir together the flour, cocoa powder, espresso powder, baking powder, and salt. Set aside. In a large bowl, using a wire whisk or an electric mixer on high speed, beat the eggs until light pale yellow. Add the sugar and vanilla and heat until well combined. Stir in the melted chocolate mixture and the flour mixture. Add 3/4 cup of the walnuts and stir to distribute evenly. Spread the mixture in the prepared baking pan. Finely chop the remaining nuts and sprinkle them evenly over the top.

5. 5

   Bake just until barely set and a toothpick inserted into the center of the brownies comes out with crumbs clinging to it, 25-30 minutes. Let cool completely in the pan on a wire rack. Invert the pan onto the rack,, lift off the pan, and peel off the foil. Transfer to a cutting board and cut into 2 1/2-inch squares. Store in an airtight container for up to 2 days.

* Per serving · 4 servings · Values may vary.