Preheat oven to 350° F. Lightly grease bottom of an 8x8-inch or 9x9-inch square baking pan with butter or shortening.
Melt butter in microwave-safe bowl. Add liqueur and eggs to the melted butter. Stir in all dry ingredients and mix just until blended. Spread batter in the prepared baking pan.
Bake for 30 to 35 minutes (8-inch pan) or 25-30 minutes (9-inch pan), or until the brownies are dry around edges. A toothpick inserted in the center should come out almost clean. Cool completely, about 1 hour.
Lightly dust brownies with confectioners’ sugar and cut into 4 rows by 4 rows to make 16 brownies.
Change the flavor profile by substituting the raspberry liqueur with your favorite flavored liqueur, such as coffee, Irish cream, black currant or orange.