Preheat the oven to 350°F (175°C) and line a cupcake pan with cupcake liners.
In a mixing bowl, cream the softened butter and granulated sugar together until light and fluffy using an electric mixer.
Add the eggs, buttermilk, vanilla extract, and peach nectar to the mixture, beating well until combined.
In another bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix.
Gently fold in the sparkling wine until evenly distributed in the batter.
Divide the batter evenly among the 12 cupcake liners, filling each about two-thirds full.
Bake in the preheated oven for 20 minutes or until a toothpick inserted into the center of a cupcake comes out clean.
Allow the cupcakes to cool in the pan for 5 minutes before transferring them to a cooling rack to cool completely.
In a mixing bowl, beat the softened butter until creamy.
Gradually add in the powdered sugar, mixing on low speed until combined. Then increase speed and whip until fluffy.
Add the peach puree, peach nectar, and vanilla extract, beating until well mixed. Add food coloring if desired and mix until combined.
Once the cupcakes are fully cooled, frost them generously with the peach frosting using a spatula or piping bag.