1. To make the champagne reduction used in the cupcakes and frosting, add all of the champagne to a medium sized saucepan and cook over medium heat until you’ve got 3/4 cup remaining. Don’t boil. To measure how much champagne remains, pour into a glass measuring cup. Add it back to the pan if it needs longer to cook down. When done, refrigerate until cool.
2. To make the cupcakes, prepare a cupcake pan with cupcake liners and preheat the oven to 350°F (176°C).
3. Combine the flour, baking powder and salt in a medium sized bowl and set aside.
4. Add the butter, sugar and oil to a large mixer bowl and beat together until light in color and fluffy, about 3 minutes. Do not skimp on the creaming time.
5. Add the eggs one at a time, mixing until mostly combined after each. Add the vanilla extract with the second egg. Scrape down the sides of the bowl as needed to be sure all ingredients are well incorporated.
6. Add half of the dry ingredients to the batter and mix until mostly combined.
7. Add the milk and champagne reduction and mix until well combined. The batter might look a little curdled, but that’s ok.
8. Add the remaining dry ingredients and mix until well combined and smooth. Scrape down the sides of the bowl as needed to be sure all ingredients are well incorporated. Do not over mix the batter.
9. Fill the cupcake liners about 3/4 full and bake for 14-16 minutes or until a toothpick inserted into the center comes out clean.
10. Remove cupcakes from the oven and place on a cooling rack to cool.
11. To make the buttercream, combine the butter and shortening in a large mixer bowl and beat until smooth.
12. Add about half of the powdered sugar and mix until smooth and well combined.
13. Add 3 tablespoons of the champagne reduction and the salt to the frosting and mix until well combined.
14. Add the remaining powdered sugar and mix until smooth. Add additional champagne reduction as needed to get the right consistency.
15. Pipe the frosting onto the cupcakes. I used Ateco tip 844. To see how to create the swirl design, see my tutorial. Add sprinkles, if desired. Note that if you’re doing to serve the cupcakes more than a few hours after adding the sprinkles, you may want to use a sprinkle that doesn’t bleed, like the ones shown.
16. Store the cupcakes in an air-tight container. Cupcakes are best if eaten within 2-3 days.