Dark Chocolate and Champagne Buttercream Cupcakes

Ingredients

• 2 cups granulated sugar
• 1-3/4 cups all purpose flour
• 3/4 cup unsweetened dark cocoa powder
• 1-1/2 tsp baking powder
• 1-1/2 tsp baking soda
• 1/4 tsp fine sea salt
• 2 large eggs
• 1 cup buttermilk
• 1/2 cup unsalted butter (1 stick), softened
• 2 tsp vanilla extract
• 1/2 cup champagne
• 1/2 cup boiling water
• 1 cup unsalted butter (2 sticks), at room temperature
• 3-1/4 cups powdered sugar
• 1 tsp vanilla extract
• 7 TBSP champagne
• 1 drop red food coloring