When cupcakes are fully cooled, use fork or wooden skewer to poke holes in tops of cupcakes, cleaning off end with paper towel as needed. In 2-quart saucepan, heat 1 cup water to boiling over high heat. Remove from heat; stir in gelatin and 2/3 cup champagne until gelatin dissolves. Use large spoon to spoon mixture evenly over cupcakes. Refrigerate cupcakes while making frosting.