Welcome to the Cake Decorators Q&A

I have a cake done wirh Mrs Jones vanilla recipe but need help for the champagne filling: ganache or buttercream with champagne flavor?

Champagne Buttercream Frosting:
In the bowl of an electric stand mixer with a whisk attachment, whip the butter until creamed. Add the powdered sugar and champagne and mix until the ingredients are evenly incorporated and the frosting is smooth and creamy.
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Champagne Ganache
Ingredients
•1 tablespoon powdered gelatin
•3 tablespoons cold water
•⅔ cup (5.33 ounces) Champagne or sparkling wine
•2 tablespoons Cognac or other brandy
•½ teaspoon vanilla extract
•¼ cup (2 ounces) heavy cream
•3 tablespoons light corn syrup
•2 cups (11 ounces) 38% milk chocolate chips, fèves, or chopped 38% milk chocolate, melted
•2 ounces 61% bittersweet chocolate, chopped and melted
•9 tablespoons (4.5 ounces) unsalted butter, softened
Instructions
1.Sprinkle the gelatin over the cold water in a small bowl. Let sit for 10 minutes, until the gelatin softens.
2.Meanwhile, pour the Champagne, Cognac, and vanilla into a measuring cup.
3.Combine the melted chocolates in a medium bowl. Pour the cream and corn syrup over the chocolates and, using a small silicone spatula, stir the mixture in one direction, concentrating on the center, until the ganache is smooth and glistening.
4.Slowly pour the Champagne into the ganache, whisking constantly (if you add the Champagne too quickly, the ganache will separate). Add the butter and stir until it is completely melted, about 1 minute. Put the ganache in the coolest part of your kitchen and let set, stirring occasionally, until spreadable, for about 1 hour before using.
5.Leftover ganache can be covered and refrigerated for up to 2 weeks; see instructions below.
Tip:
1.Chill the Champagne before uncorking it. Opening a bottle of room–temperature Champagne is dangerous, as the cork is likely to explode out of the bottle.
have used both, the first with raspberry cupcakes and the second with a vanilla butter pound layer anniversary cake and a birthday cake. Both were well received. I don’t remember where I found the later recipe, the first was just experimenting.