1

Preheat oven to 350°F. Butter 8x8-inch square baking pan. Line with parchment paper and butter parchment.

2

In a medium bowl, sift together flour, cocoa powder, and salt; set aside.

3

In a large, heavy-bottomed saucepan, combine butter and espresso. Place over low heat and stir until butter has melted. Add chocolate, and stir constantly until mixture is smooth, about 2 minutes. Remove from heat, and stir in both sugars until well combined.

4

Add eggs and vanilla and continue stirring until well incorporated and mixture no longer appears grainy. Sift mixture over batter, and stir until just combined. Stir in chocolate chips, if using.

5

Pour batter into prepared pan; smooth top with back of a wooden spoon or a spatula. Bake until a toothpick inserted in the center comes out with a few moist crumbs, 28 to 30 minutes. Be sure not to over bake. Let cool completely on a wire rack. Cut into 9 brownies.