Preheat the oven to 350°F.

Spray a 9x9-inch metal pan with non-stick spray. Set aside.

Melt the semi-sweet chocolate chips and salted butter together. Set aside to cool slightly.

In a small bowl, sift together the flour, cocoa powder, espresso powder, and salt. Set aside.

In a large bowl, beat the eggs, granulated sugar, and vanilla with an electric mixer for three minutes until pale in color.

Add the melted chocolate and butter to the egg mixture. Gently fold until combined.

Fold in the dry ingredients just until combined.

Pour the batter into the prepared pan.

Bake the brownies for 34-40 minutes, until the center only wobbles slightly when the pan is shaken.

Let the brownies cool completely, for at least three hours, before cutting. They will finish baking as they cool. Cutting them too soon will make them seem underbaked and gooey. Once fully cooled, remove the brownies from the pan and cut into 16 squares. Enjoy!