1. Preheat oven to 350°F. Line bottom and sides of a 9-inch square pan with aluminum foil, allowing 2 to 3 inches to extend over sides; lightly grease foil.

2. Microwave chocolate chips and butter in a large microwave-safe bowl at HIGH 1½ to 2 minutes or until melted and smooth, stirring at 30-second intervals.

3. Whisk in sugar. Add eggs, one at a time, whisking just until blended after each addition. Gently stir in flour, green food coloring, baking powder, vanilla, and salt. Pour mixture into prepared pan.

4. Bake for 44 to 48 minutes or until a wooden pick inserted in the center comes out with a few moist crumbs. Cool completely on a wire rack (about 2 hours).

5. For the frosting: Beat cream cheese and butter at medium speed with an electric mixer until creamy. Gradually add powdered sugar and salt, beating until blended. Stir in vanilla.

6. Lift brownies from pan, using foil sides as handles; gently remove foil. Spread Cream Cheese Frosting on top of brownies, and cut into 16 squares. Garnish, if desired.