ESPRESSO KAHLUA BUTTERCREAM CHUNK BARS

1 cup flour
Heaping 1/2 teaspoon baking powder
1/8 teaspoon salt
1/2 cup unsalted butter, melted
1 cup firmly packed light brown sugar
2 teaspoons instant espresso powder
1 teaspoon vanilla extract
1 large egg
3/4 cup bittersweet or semisweet chocolate chunks (1/2-inch), about 3 3/4 ounces
1 tablespoon Kahlua liqueur (for topping)
FOR THE FROSTING:
6 tablespoons (3/4 stick) unsalted butter, softened
1 3/4 cups plus 2 tablespoons powdered sugar
1 tablespoons plus 1 teaspoon milk
1 tablespoon plus 2 teaspoons Kahlúa liqueur
1 1/2 teaspoons instant espresso powder

TO MAKE THE BARS:
Preheat oven to 350 degrees F. Coat 8-inch square baking pan with nonstick cooking spray.

Whisk flour, baking powder and salt together in small bowl. In large bowl whisk together melted butter and brown sugar. Whisk in espresso powder, vanilla and egg, blending well. Stir in flour mixture, mixing just until blended. Cool mixture; stir in chocolate chunks. Spread evenly in pan.

Bake until light golden brown, slightly puffed and edges begin to pull away from pan, about 30 minutes. Brush top with Kahlua. Cool on rack.

TO MAKE THE FROSTING:
Beat all ingredients together at medium speed until creamy. Increase speed to high; beat until light, creamy and smooth, about 3 minutes.

Spread frosting over cooled brownies. Cut into 20 bars.

Makes 20 bars
Source: A Baker's Field Guide to Chocolate Chip Cookies by Dede Wilson