Preheat oven to 350°F. Line a 13x9 inch metal pan with nonstick foil or parchment paper.
Stir together cocoa and baking soda in large bowl. Add half (1/3 cup) of the melted butter and stir until smooth, then add boiling water and stir until mixture thickens. Stir in Irish Cream, sugar, eggs and remaining 1/3 cup butter.
Add flour, vanilla and salt; blend completely. Stir in chocolate chips. Pour into prepared pan and spread evenly.
Bake 35 minutes or until brownies begin to pull away from sides of pan. Let cool completely in pan on wire rack. If desired, brush the warm brownies with more Irish Cream.
To make the frosting, beat the cream cheese and butter together, then add 1 1/2 cups of powdered sugar and beat until thick. Begin adding Irish Cream, beating until mixture is smooth and creamy. beat until light and creamy. Frost the brownies when they are cool.
Lift from pan, set on a cutting board and cut into 16 squares.