Unicorn Cupcakes are astonishingly pretty, delicious and also easy to make. Perfect for themed parties, these are meant to be a hit with everyone.
Slowly, with the mixer on low speed, add the water and 10 drops of purple gel food color to the batter and mix just until combined. Scrape down the sides of the bowl as needed to make sure everything is well combined. If you want the color more intense, add more gel color, stir to combine, careful not to over-mix.
Bake for 15-20 minutes, or until a toothpick comes out with a few moist crumbs NOT raw batter. In my oven, the cupcakes were perfectly done at the 20-minute mark. Do NOT open the oven until 15 minutes have passed. Start checking on the cupcakes at the 15-minute mark. If you are baking mini cupcakes, they may be done in 9-12 minutes, start checking after 9 minutes.
Remove the cupcakes from oven and allow to cool for 3-5 minutes in the pan, then remove to a cooling rack to finish cooling.
Add the remaining 4 cups of powdered sugar and mix until smooth. If the buttercream is too soft, add more sugar, 1/2 cup at a time.