8 ounces bittersweet chocolate, cut into ¼-inch pieces
2 tablespoons cocoa powder
2 sticks (1 cup) unsalted butter
1 cup sugar
1 cup light brown sugar, packed
1 tablespoon vanilla extract
1 teaspoon kosher salt
1 teaspoon instant espresso powder
4 eggs
1 cup all-purpose flour
½ cup semisweet chocolate chips
½ cup milk chocolate chips
Directions
Preheat the oven to 350° and line a 9-inch square pan with parchment paper.
In a medium glass bowl, combine the bittersweet chocolate, cocoa powder and butter. Set the bowl over a small saucepan of simmering water and let melt, stirring occasionally until a smooth ganache comes together.
Meanwhile, in a large mixing bowl, mix the sugars, vanilla extract, salt, instant espresso powder and eggs until well incorporated. Once melted, stir the chocolate mixture into the bowl with the sugar mixture until smooth. Fold in the flour until a batter comes together followed by the semisweet and milk chocolate chips.
Pour the batter into the prepared pan and bake until just set, 35 minutes. Let cool completely, then remove from the pan and cut into 16 squares, and serve.