Preheat oven to 325 degrees F. Fold a 16″ long piece of foil to a 9″x16″ strip and place in 9″x9″ metal baking pan, leaving overhang on 2 sides. Repeat with another sheet of foil the same size in the opposite direction, lining pan completely. Spray foil with nonstick spray.

Stir butter and chocolate in heavy large saucepan over very low heat until chocolate is melted. Remove from heat.

Whisk in sugar, then eggs, 1 at a time. Stir in vanilla, salt, and food coloring.

Sift flour and baking powder over mixture and stir to blend well. Transfer batter to prepared pan.

Bake brownies until puffed and dry-looking and tester inserted into center comes out with some moist batter attached, about 30 to 35 minutes. Cool completely in pan on rack.

Prepare the frosting by first beating together the cream cheese and butter until light and fluffy. Add vanilla and mix a bit to incorporate. Then add the sifted powdered sugar and beat to combine.

Using the foil as an aid, lift brownies from pan and place on cutting board. Peel foil down away from the sides of brownies. Spread cream cheese frosting evenly over brownies. Sprinkle with edible glitter, if desired. Cut into bites 1-1/4″ x 1-1/4″. To achieve clean cuts, wipe the knife after each slice.