a piping bag fitted with a large star tip; four 8-ounce mason jars
Cut the cupcakes in half horizontally. Transfer the vanilla frosting to a piping bag fitted with a large star tip. Pipe approximately 2 tablespoons frosting into each of four 8-ounce mason jars. Drop a cupcake bottom into each jar and press down slightly. Top with 2 more tablespoons frosting each. Cover each frosting mound with 1 tablespoon confetti sprinkles, making sure to sprinkle them to the edges so they are visible on the outside of the jar. Top with the top halves of the cupcakes; press down slightly. Pipe approximately 1/3 to 1/2 cup frosting on top of each cupcake in a large swirl. Cover each swirl with 1 tablespoon confetti sprinkles. Serve immediately.