To make the frosting:
In the bowl of an electric stand mixer fitted with a whisk attachment, mix together butter and sugar on low speed until well blended. Add vanilla extract, champagne, and food coloring, and beat on medium speed until the ingredients are evenly incorporated and the frosting is smooth and creamy. Add more champagne if necessary to achieve desired consistency.
To make the cupcakes:
Preheat oven to 350 F and line muffin tins with paper cups.
In a medium bowl, sift together flour, baking powder, baking soda, and salt. Set aside.
In a large bowl, whisk to combine eggs, sugar, vanilla, and canola oil. Add flour mixture in three portions, alternating with the buttermilk (beginning and ending with the flour), beating well after each addition.
Fill muffin tins to about two-third full. Bake for 12-14 minutes or until a toothpick inserted in the center comes out clean. Let cool in pan for 10 minutes then remove to a wire rack to cool completely.