These ice-cream cupcakes make memorable party treats. Chilling the bowl beforehand helps the cream whip up with the most volume.
Place 30 paper baking cups on two baking sheets. Set aside. Slice each cake layer in half horizontally, making a total of four layers.
Using a 2 1/4-inch-round cookie cutter, cut 30 rounds from cake layers. Place a round in each baking cup. Using a 2-inch ice-cream scoop, place one scoop ice cream on each cake round. Transfer baking sheets to freezer for 20 minutes. Chill a medium mixing bowl.
Place heavy cream and confectioners' sugar in the chilled bowl. Whip until soft peaks form. Fit a 16-inch pastry bag with a coupler. Fill pastry bag with whipped cream. Starting at the perimeter of a baking cup, pipe a spiral of whipped cream, covering the ice cream. Repeat with remaining cupcakes. Return to freezer, and chill until hard, about 45 minutes. Decorate with sprinkles, and serve.