• Preheat the oven to 350 degrees F. Line 12-cup cupcake pan with liners. Pour the champagne into a bowl and whisk until the bubbles dissipate. Combine 1/2 cup of the champagne and the vanilla extract in a small bowl. Set aside the remaining champagne for the frosting.
• Whisk the flour, baking powder and salt in a medium bowl. Beat the butter and sugar in a large bowl with a mixer on medium-high speed until light and fluffy (about 5 minutes). Add the egg and beat until smooth. Beat in the flour mixture alternating with the champagne-vanilla mixture until just combined.
• Divide the batter evenly into 12 muffins tins and bake for 20-25 minutes until they're lightly brown on top and a toothpick inserted comes out clean.

Frosting

• To make the frosting whip together remaining butter, and confectioner's sugar. Add champagne beating for another minute. If you need it to thicken, put it in the refrigerator for 10-15 minutes so it's easier to work with.