The secret to making these funfetti cupcakes super fluffy and delicious? Sprite! 1) Preheat oven to 350 degrees Fahrenheit. Line a muffin tin with cupcake liners. 2) To a large bowl add funfetti cake mix and Sprite. Beat until fully combined and creamy. 3) Scoop or pipe batter into cupcake liners. Bake for 20 minutes or until baked through. Remove from oven and cool. 4) While cupcakes cool, making your frosting. In a bowl beat together powdered sugar and butter. Beat in vanilla and milk, continue beating until mixed and creamy. If the frosting is too thick, add a little more milk. Refrigerate frosting for 20 minutes. 5) Once cupcakes and frosting are cooled, scoop frosting into a piping bag or a ziplock bag with the corner cut off. Pipe frosting onto cupcakes and sprinkle with coconut flakes and rainbow sprinkles. Serve and enjoy!