Preparation Preheat oven to 325°F. Line 13x9x2-inch metal baking pan with foil. Butter foil. Combine 3/4 cup butter, chocolate, and espresso powder in heavy large saucepan; stir over medium-low heat until chocolate is melted and smooth. Remove chocolate mixture from heat. Add sugar and vanilla and whisk until well blended. Add eggs and whisk until well blended. Whisk in flour. Spread batter in prepared pan. Press milk chocolate squares lightly into batter (do not submerge), evenly spacing 24 chocolate squares (4 across the short side and 6 across the long side). Reserve remaining chocolates for another use. Bake brownies until tester inserted into center comes out with some moist crumbs attached, about 27 minutes. Cool slightly in pan on rack, about 30 minutes. Cut so that each brownie has 1 chocolate square and serve.
Preparation Preheat oven to 325°F. Line 13x9x2-inch metal baking pan with foil. Butter foil. Combine 3/4 cup butter, chocolate, and espresso powder in heavy large saucepan; stir over medium-low heat until chocolate is melted and smooth. Remove chocolate mixture from heat. Add sugar and vanilla and whisk until well blended. Add eggs and whisk until well blended. Whisk in flour. Spread batter in prepared pan. Press milk chocolate squares lightly into batter (do not submerge), evenly spacing 24 chocolate squares (4 across the short side and 6 across the long side). Reserve remaining chocolates for another use. Bake brownies until tester inserted into center comes out with some moist crumbs attached, about 27 minutes. Cool slightly in pan on rack, about 30 minutes. Cut so that each brownie has 1 chocolate square and serve.