Fondant roller or rolling pin; 2-inch heart cookie cutter; 6 pencils, pens or chopsticks; small paintbrush
For the wings: Dust the work surface lightly with confectioners' sugar. Roll the yellow fondant out to a thickness of 1/8 inch, moving the fondant occasionally as you roll to make sure it does not stick. Cut out 24 hearts with a 2-inch heart cookie cutter.
Arrange the pencils, pens or chopsticks on the work surface. Pair hearts together by overlapping their points by an inch. With a small brush, dab a little water on the overlapping area between the 2 fondant pieces and press gently to adhere. Drape each pair of wings over a pencil to shape the butterfly. Allow to dry until stiff, about 2 hours.
For the antennae: Unroll the licorice and cut into twelve 1 1/4-inch-long pieces. Separate the two strands of each licorice piece, leaving them attached at one end. Roll 2 small (1/4-inch) balls of green fondant for each pair of antennae and attach the balls to one end of the licorice. Enclose the remaining fondant in plastic wrap so it does not dry out. Repeat with the remaining pairs of antennae. Set aside to dry.
For the bodies: Shape about 2 teaspoons green fondant into a butterfly body, about 2 inches long, with a head at one end and the other end tapering to a point. Attach a pair of antennae by sticking the licorice into the head. Using a small brush, moisten the front of the body with a little water and attach 2 yellow sprinkles for eyes.
To assemble and decorate: When the wings are dry, turn them over and place between 2 pencils for support. Brush the center of each with a little water; add a body and press gently to adhere. Brush the wings lightly with water and stick on the multicolored sprinkles to decorate. Let dry 30 minutes.
Melt the chocolate. Add pupils to the eyes by dipping a skewer into the melted chocolate and making a small dot on each yellow sprinkle.
Frost each cupcake with about 2 tablespoons buttercream. Top each cupcake with a butterfly and press them gently into the frosting to adhere.