Combine cupcakes ingredients in a large bowl or stand mixer and beat until well combined.
Fill cupcake liners 2/3 of the way full.
Bake for 15-18 minutes or until toothpick comes clean when inserted into the center of a cupcake.
Remove from oven and allow cupcakes to cool in pan for a couple of minutes.
Transfer to a cooling rack and allow to cool completely before frosting.
Frosting:
Cream butter.
Add confectioner's sugar a ½ cup at a time.
Beat on high for about 3 minutes, frosting should be fluffy and smooth.
Add champagne and beat for 2 more minutes.
Frost cupcakes.
Dust frosting with shredded coconut and gold sprinkles.
Notes
If using a different white cake mix, just replace the amount of water with coconut milk and use the amount of egg whites indicated on the back of the box.