Preheat the oven to 350°F. Butter an 8x8-inch square baking pan. Line with parchment paper and the butter the parchment too.
In a medium bowl, sift together the flour, cocoa powder, and salt; set aside.
In a large saucepan, combine the butter and espresso. Place the pan over low heat and stir until the butter has melted. Add the chocolate, and stir constantly until the mixture is smooth, about 2 minutes. Remove from heat, and stir in both sugars until well combined.
Add the eggs and vanilla and continue stirring until well incorporated and the mixture no longer appears grainy. Sift the flour mixture over the batter, and stir until just combined. Stir in the chocolate chips.
Pour the batter into the prepared pan; smooth the top with the 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 the brownies cool completely on a wire rack. Cut into 9 brownies.