In a saucepan over medium-low heat, gently simmer the champagne (do not let it boil) until it reduces to half its original volume. Remove from heat and place in the refrigerator to chill.
In a medium bowl, whisk together the flour, baking soda and salt. Set aside.
In a large bowl, use an electric mixer to cream together the granulated sugar, butter, and oil (about three minutes) until light and fluffy. Add in vanilla and eggs, one at a time, mixing until incorporated.
Pour in ½ cup of the champagne reduction and milk. Continue to stir until fully incorporated. It’s okay if the batter starts to look curdled. Stir in the dry cupcake ingredients, mixing until just combined (do not overmix).
Pour batter into a lined cupcake pan to about ¾ full each and bake on middle rack of a preheated 350℉ oven for 14 - 16 minutes until fully cooked (use toothpick to confirm doneness). Remove to wire rack and allow to cool completely.
Frosting
While cupcake are cooling, use an electric mixer to beat the butter until smooth and creamy (1-2 minutes). Slowly add the powdered sugar in ½ cup increments. Mix until thoroughly incorporated.
Pour in remaining ¼ cup of champagne reduction and mix well.
Pipe onto cupcakes and top with sprinkles (we used a 1mm star tip).
Notes
Calories are automatically generated. For best results calculate based on your exact ingredients.