Preheat oven to 350 degrees F. Line 2 muffin tins with 16 paper liners; set aside.
Beat the cake mix, champagne, buttermilk, oil, and egg whites together with an electric mixer for 2 minutes or until thoroughly combined. Portion the batter evenly among the muffin tins, filling about 2/3 to 3/4ths full.
Bake for approx. 14-17 minutes or until a toothpick inserted near the center comes out clean or with moist crumbs. Cool completely.
In the bowl of a stand mixer, cream together the butter and vanilla until whipped, about 1 minute. Add in the powdered sugar, one cup at a time, beating well after each addition. In between additions of powdered sugar, add 1 Tablespoon heavy cream and 1 Tablespoon pink champagne and beat well. After the last powdered sugar addition, beat on medium-high speed for 1 minute until fluffy and light. Beat in the food coloring, if using.
Frost or pipe onto cooled cupcakes and top with a fresh raspberry and a sprinkling of sugar and sprinkles, if using. Store airtight in the fridge or at room temperature.
NOTE: if frosting the cupcakes very high like I have in my photos, I suggest doubling the frosting.