For the Cupcakes:

1. Preheat your oven to 350°F (175°C) and line a cupcake pan with paper liners.
2. In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
3. In a large bowl, beat the butter and sugar with an electric mixer until light and fluffy, about 2–3 minutes.
4. Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
5. Mix in the sour cream until smooth.
6. Alternate adding the dry ingredients and pink champagne, starting and ending with the dry ingredients. Mix just until combined. If desired, add a few drops of pink food coloring to achieve a pastel pink hue.
7. Divide the batter evenly among the cupcake liners, filling each about 2/3 full.
8. Bake for 18–20 minutes, or until a toothpick inserted into the center comes out clean. Let cool completely on a wire rack before frosting.

For the Champagne Buttercream Frosting:

1. Beat the butter in a large bowl with an electric mixer until creamy.
2. Gradually add the powdered sugar, one cup at a time, mixing well after each addition.
3. Add the pink champagne and vanilla extract, mixing until the frosting is smooth and fluffy. Adjust the consistency by adding more champagne if needed.
4. If desired, tint the frosting with pink food coloring.

Assemble the Cupcakes:

1. Transfer the frosting to a piping bag fitted with your favorite tip.
2. Pipe the frosting onto the cooled cupcakes.
3. Garnish with sprinkles, edible glitter, or a small fondant decoration for a festive touch.