To make the fondant Mickey ears, dust your surface and rolling pin with powdered sugar and roll out the black fondant to ¼" thick. Cut out 24 x 4" circles with a round cutter. Place onto a cookie sheet lined with parchment paper.
To make the fondant Jack faces dust your surface and rolling pin with powdered sugar and roll out the white fondant to ¼" thick. Cut out 24 x 2" circles with a round cutter.
Attach the white circle to the black circle by brushing some water over the back of a white circle and sticking in the middle of the black one. Repeat for all the ear pieces and leave to dry for at least 6 hours, and up to 24 hours if possible.
To make the bows, use about one tablespoon of black fondant and press it into a bow mold. Carefully remove and place on a cookie sheet to dry for at least 6 hours. Again, 24 hours is best. Make 12 bows in total (with a few extras as before!).
Make a few extra fondant decorations as backup, just in case!
When the ears are dried, draw Jack's face on with a black edible marker.
Preheat oven to 180C/350F/Gas 4 degrees and line cupcake pan with cupcake liners.
Using an electric mixer, mix the cake mix with the milk, eggs, and softened butter until combined.
Use an ice cream scoop to fill cupcake liners and bake for 20 minutes or until a toothpick comes out clean when inserted into center of cupcake.
Allow to cool in pan for 5 minutes before transferring to a wire rack to cool completely.
To make the frosting, use an electric mixer to combine the butter, powdered sugar, heavy whipping cream, and vanilla on medium speed until combined and smooth.
Scoop the frosting into a piping bag fitted with a large star tip.
Pipe frosting swirls onto the cooled cupcakes.
Place the bow in the middle of the frosting.
Place the Mickey ears on either side of the bow.