Pour the champagne or sparkling white grape juice into a medium saucepan. Cook over a medium-low heat until you have a recduction of 3/4 cup remaining. Be sure not to boil. Refrigerate until cool.
Preheat oven to 350° and prepare a cupcake pan with 12 cupcake liners.
Combine the flour and baking powder in a medium-sized bowl and set aside.
Place butter, sugar and oil in a large mixing bowl and beat until light and fluffy.
Add the eggs one at a time, mixing after each until combined. Add in the vanilla extract with the second egg and mix. Scrape down the sides of the bowl often.
Add half of the dry ingredients and mix until combined.
Add the milk and champagne reduction and mix until thoroughly incorporated.
Add the remaining dry ingredients and mix until well combined and smooth. Be sure not to overmix the batter.
Fill the cupcake liners about 3/4 full and bake for approximately 15 minutes, or until a toothpick inserted in the center comes out clean. Remove to cooling rack to cool completely.
Buttercream Frosting
Using an electric mixer with a paddle attachment beat together the shortening and butter in a large bowl until light and fluffy. Beat in the vanilla. Using the paddle attachment instead of the whisk will help prevent air bubbles.
Add sugar gradually, beating slowly at first and then beating well on a medium speed. Scrape the sides and bottom of the bowl frequently.
Gradually add milk or water, while beating at a medium speed, until the mix is light and fluffy. Add in the extract and mix.
Using a piping tip of your choice, (I used a large open star tip) ice the cupcakes and decorate with additional items if you choose.