Cut cake horizontally to make 3 layers; split layers in half to make 6 total. Press 1 layer in bottom of 9x5-inch loaf pan. Remove ice cream from freezer; carefully lift ice cream from pan and remove plastic. Place 1 ice cream layer on cake in pan; top with second cake layer. Repeat layers. Return to freezer. Repeat for second cake. In large bowl, beat whipping cream and powdered sugar with electric mixer on high speed until stiff peaks form. Spread whipped cream over cake. Serve, or freeze up to 8 hours. Before serving, sprinkle cake with crushed candies.