Building Blocks Cakes

Heat oven to 350°F (325°F for dark or nonstick pan). Grease or spray bottom and sides of 13x9-inch pan.

Make and bake cake mix as directed on box for 13x9-inch pan. Cool in pan 10 minutes; remove from pan to cooling rack. Cool completely, about 1 hour. Refrigerate or freeze cake about 1 hour or until firm.

Meanwhile, in small bowl for each color, tint 1 cup frosting red, 1 cup frosting yellow and 2/3 cup frosting blue with food colors. Leave remaining frosting white.

Using serrated knife, cut rounded dome from top of cake to make flat surface; place cake cut side down. Cut cake crosswise into thirds. Cut one of the thirds in half crosswise to make 2 squares. Place cake pieces on tray.

To seal in crumbs, frost top and sides of 1 square cake with thin layer of blue frosting and 1 square cake with thin layer of white frosting. Frost 1 rectangular cake with thin layer of yellow frosting and 1 rectangular cake with thin layer of red frosting. Refrigerate or freeze 30 to 60 minutes to set frosting.

Add final coat of frosting to each cake. Frost 4 marshmallow halves with blue frosting; place in square design on blue cake. Frost 4 marshmallow halves with white frosting; place in square design on white cake. Frost 8 marshmallow halves with yellow frosting; place on yellow cake. Frost 8 marshmallow halves with red frosting; place on red cake. Store loosely covered.