To assemble, remove paper baking cups, and cut cupcakes in half horizontally. Set aside 16 cupcake tops. Pipe about 1 tablespoon frosting onto cut side of 16 cupcake bottoms; top each with another cupcake top or bottom. Pipe about 1 tablespoon frosting on each cupcake. Top with reserved cupcake tops. Pipe frosting on cupcake tops. Decorate with sprinkles, if desired. Store in refrigerator until serving.