Rainbow Layer Cake with Rainbow Chip Frosting

Heat oven to 350°F. Spray 3 (8-inch) round cake pans with cooking spray.

In large bowl, beat cake mixes, water, oil and eggs with electric mixer on low speed 30 seconds, then on medium speed 2 minutes, scraping bowl occasionally. Divide batter evenly among 6 small bowls, about 1 1/3 cups each.

Using food colors, tint batter in 1 bowl blue, 1 bowl red, 1 bowl green, 1 bowl yellow, 1 bowl orange (using red and yellow) and 1 bowl purple (using blue and red).

Refrigerate 3 colors of batter until ready to bake. Pour remaining 3 colors of batter into cake pans.

Bake 18 to 20 minutes or until cake springs back when touched lightly in center and begins to pull away from side of pan. Cool 10 minutes. Remove from pans to cooling racks; cool completely, about 1 hour.

Wash cake pans. Bake and cool remaining 3 cake layers as directed.

Trim rounded tops off cakes to level, if needed. On serving plate, place purple cake layer. Spread with frosting to within 1/4 inch of edge. Repeat with blue, green, yellow, orange and red cake layers. Spread light coat of frosting on side and top of cake to seal in crumbs, then frost again with remaining frosting.