Preheat oven to 350°F. Grease 8-inch square baking pan. Melt chocolate and butter in medium, heavy saucepan over low heat, stirring constantly. Remove from heat. Stir in sugar. Beat in eggs, 1 at a time, with wire whisk. Whisk in liqueur. Combine flour, baking powder and salt in small bowl; stir into chocolate mixture until just blended. Spread batter evenly in prepared pan.

Bake 22 to 25 minutes or until center is set. Remove pan to wire rack; cool completely. Prepare Irish Cream Frosting; spread over cooled brownies. Chill at least 1 hour or until frosting is set. Cut into 2-inch squares.

Beat cream cheese and butter in small bowl with electric mixer at medium speed until smooth. Beat in liqueur. Gradually beat in powdered sugar until smooth.