Whenever we find ourselves with some champagne left over in an open bottle, this is my favorite way to use it:
Fill a med mixing bowl a third of the way with ice water, or fill a sink partially with ice water.
Fill the bottom of a double boiler partially with water. Bring the water to a boil.
Combine 6 egg yolks, 2/3 C. champagne and 1/3 C. sugar in the top of a double boiler, or (my pref) a bowl that will fit over the bottom of the double boiler comfortably w/ out touching the water. Whisk it until blended, then set it over the hot water in the bottom of the double boiler. Cook it until it's thick, stirring constantly. This should take about 3 minutes. Then immediately take the bowl with the champagne sabayon and put it in the waiting ice water to cool, whisking often as the temp comes down.
In another bowl, whip 3/4 cup heavy whipping cream, then fold into the cooled sabayon.
You can serve the sabayon with any type of cake, it even makes store-bought pound cake elegant, but it comes from a recipe for Rasberry
Champagne Cream Cake from "Four-Star Desserts" by Emily Luchetti.
To make this beautiful cake, you'll need 2 8" Vanilla Genoise cakes and about a cup of Rasberry Puree (I use the recipes from Cake Bible for this). Line the bottom of an 8" springform pan with parchment paper. Cut the two cakes in half horizontallly. Then place one cake piece cut side up in the bottom of the pan. Spread on 1/4 of the raspberry puree, then 1/3 of the sabayon. Place the second cake piece on top, cut side down. Continue the layering with the last cake piece cut side down, and ending with just the puree. Then you can frost the cake w/ a whipped cream frosting (or a white chocolate ganache) and decorate with raspberries.
Happy New Year!