Hot Fudge Cake
["1 yellow, chocolate or white cake mix", "4 c. confectioners sugar, sifted", "6 to 8 Tbsp. cocoa, sifted", "2 c. evaporated milk", "1 stick margarine", "1/2 gal. vanilla or chocolate ice cream"]
["Cook cake as directed on package in a 9 x 13-inch pan.", "Cool. Cut into squares."]
["chocolate", "confectioners sugar", "cocoa", "milk", "margarine", "vanilla"]