Follow the instructions on the cake mix box to make cupcakes. After baking, set aside to cool completely.
Press the non-decorative side of a large decorating tip into the top of each cupcake to form a well. Save the pieces.
Roll the black fondant to 1/8-inch thick on parchment powder. Lightly dust with powdered sugar if fondant is too sticky.
Using a circle cookie cutter, cut out 24 fondant rounds. Remove the excess fondant. Use a damp paper towel to brush away any remaining powder sugar from the circles. Set aside circles to dry for at least two hours (overnight is better).
Add 5-10 drops of blue food coloring to half of the frosting, stirring well to incorporate the color completely into the frosting. Using a fine paintbrush, apply a small triangle of blue frosting on each fondant circle to create the bodice of Anna's dress.
In a small bowl, add 3-5 drops of water to a teaspoon of edible gold glitter. Using the paintbrush, outline the light blue triangle with gold and draw some swirls on the rest of the circle.
On a section of the parchment paper away from the circles, combine 1/2 teaspoon of frosting with 2 drops of red, 1 drop of black, and 1 drop of purple food coloring. Use the paintbrush to apply small circles of burgundy on the fondant circles to create the jewels.
Place 2/3 of the remaining white frosting and all of the remaining blue frosting in a decorating bag with a large star tip.
Starting on the outer edge of the cupcake, pipe the frosting in a circular pattern working in towards the center.
Add purple sprinkles to each cupcake on top of the frosting.
Carefully insert two of the fondant ears into each cupcake, one on each side. Place the cupcakes in the refrigerator for 15-20 minutes to set.
Pipe a final dollop of white frosting onto each cupcake. The cupcakes are ready to serve!