Mint Chocolate Ice Cream Cake

I thought I'd posted this recipe before, but I can't find it, and Sarah wanted a copy, so here goes:

Cake
1 box Betty Crocker SuperMoist butter recipe chocolate cake mix
Water, butter, and eggs called for on cake mix box

Filling
6 cups green mint-flavored ice cream with chocolate chips or chocolate swirl, slightly softened

Frosting
1 1/2 c whipping cream
2 T powdered sugar
4 drops green food color

Heat oven to 350 degrees. Grease bottoms only on 2 9-inch round cake pans; line bottoms with waxed paper. Make cake mix as directed on box. Spoon evenly into pans.

Bake as directed on box. Cool in pans 10 minutes. Remove from pans to cooling racks. Remove waxed paper. Cool completely, about 30 minutes.

Line 9-inch round cake pan with foil. Spoon and spread ice cream evenly in pan. Cover with foil; freeze until completely frozen, about 2 hours.

On serving plate, place 1 cake layer with rounded side down. Remove ice cream from pan; peel off foil. Place on top of cake. Top with remaining cake layer, rounded side up.

In medium bowl, beat whipping cream, powdered sugar and food color on high speed until stiff peaks form. Frost side and top of cake with whipped cream. Freeze about 2 hours or until firm. Let stand at room temperature 10 minutes before serving.