Strawberry Champagne Cupcakes

Preheat the oven based on cake mix box instructions and grease the bottom and sides of a cupcake tin, or fill each cup with cupcake liners. Make the Cupcakes: Beat cake mix and Champagne until thoroughly combined (it will be bubbly). Fold in strawberries, then fill each cup of the muffin tin about two-thirds of the way full with cake mix. Bake according to the box instructions for cupcakes—typically 350 degrees F for 18-20 minutes—or until a toothpick inserted in the center comes out with just a few crumbs (no gooey batter). Set them aside to cool. Make the Frosting: In a medium-sized mixing bowl, beat sugar and butter on low until combined. Gradually stir in vanilla extract and Champagne, starting with just 1 tablespoon and gradually adding more until the consistency is smooth and easy to spread. (If it gets too thin, add a spoonful of powdered sugar.) Frost each cupcake. Make the Strawberry Topping: Slice strawberries and add sugar. Let them sit for 15 to 20 minutes to release juices, then top each cupcake with a slice.