In small bowl, mix egg whites and champagne. Set aside.
In a medium-sized bowl, whisk together cake flour, sugar, baking powder, and salt.
Mix butter into dry ingredients until it resembles moist crumbs.
Mix wet ingredients into dry ingredients until fully combined.
Divide evenly between twelve cupcake liners. Bake for 20 minutes or until cupcakes bounce back when lightly touched.
Filling and Frosting Directions:
Melt two tablespoons of butter in a medium-sized skillet on medium heat.
Drain and discard liquid from peach can.
Use a towel to pat dry the peach slices, removing excess moisture.
Place the peaches in a single layer in the hot skillet.
Cook for about three minutes or until the bottom side is browned, then flip.
Repeat until all sides of the peaches are browned.
Remove peaches from skillet and cool.
Use a food processor or immersion blender to puree the peaches.
Use a small paring knife or cupcake corer to remove a piece of cake from the center of each cooled cupcake. (You will not need the pieces that you remove, so feel free to eat them!)
Fill each hole with approximately two teaspoons of the peach puree.
In the bowl of an electric mixer, beat butter on high speed for five minutes.
Slowly mix in the powdered sugar and beat for another five minutes.
Mix in vanilla extract, salt, and ¼ cup of peach puree and beat for two minutes.