Prepare yourselves for something unexpected: I'm about to give you a recipe. You really ought to take advantage of this rare occurrence. Stick some paper in your printer now, because you will be printing this out for the next time you make cake or cupcakes.
I've been eating this frosting once a year when my mom makes my great-grandmother's hazelnut torte, but I've decided that it is officially too good to have just once a year. I made it this weekend on a chocolate cake (that you will see soon), and it was just as good on chocolate as it is on hazelnut. For frosting this rich, it's not overwhelming, because it's whipped. If you like more sweet icing, use all bittersweet, but I'm a fan of the unsweetened. And depending on how much cake you have, you will quite possibly want to double this recipe. You'll want to make extra.
Sylvia's Mocha Frosting
In a double boiler, melt 2 oz bittersweet chocolate and 1 oz unsweetened chocolate with a splash of extremely strong coffee (as strong as possible). Turn off the burner and add 1 tablespoon of brandy or sherry. Add three egg yolks, beating with an electric mixer after each one. Add half a pound of butter and beat. Add confectioner's sugar to taste, probably about two cups, and beat and beat. Chill, then spread.