Here's a cake I hadn't tried before, but will definitely make again. Looks so fancy and complicated, but it comes together very quickly. (A little hint: even if your squabbling "helpers" distract you and you forget to add the flour to the sponge cake batter, the final result will still be edible. Next time decline "help" until the decorating stage.) The sponge cake is really just a vehicle for the filling, something to spread the chocolate on. I've got some other flavor combinations swimming about in my brain...lemon sponge with berry jam and whipped cream, something with peaches and pecans....
Anyhow, there are a lot of directions here, but don't be discouraged. Just read them through a couple of times beforehand. It's actually quite a simple procedure once you try it. The kids helped with the decorating and it still turned out pretty professional looking, so you can do it, too! (Chocolate and powdered sugar look good in any form, right?)
1/4 cup sugar
4 large eggs, separated
3 Tbsp. sifted all-purpose flour
pinch of salt
6 ounces semisweet chocolate
1 ounce unsweetened chocolate
3 Tbsp. prepared coffee
3 Tbsp. unsalted butter
2 Tbsp. rum
1 cup chocolate shavings (use a swivel vegetable peeler to shave curls off a bar of chocolate--any kind but unsweetened--work over a piece of wax paper and refrigerate the shavings until ready to use)
Heat oven to 350 degrees. Line a jelly-roll pan (mine is 17"x11") with foil and grease it well with butter or baking spray.
With an electric mixer, beat 3 Tbsp. of sugar (reserve 1 Tbsp.) with the egg yolks at high speed until they are cream colored (about 5 minutes). Add the flour and beat on low, just until incorporated.
In a second bowl, with clean beaters (or the whisk attachment on a stand mixer), beat the egg whites and pinch of salt until they begin to thicken. Add the reserved tablespoon of sugar, and beat until the whites hold their shape, but are not yet stiff and dry.
Fold one-third of the whites into the yolk mixture, then another third, and then the final third. Do not mix more than necessary. Quickly and gently spread the batter into the jelly-roll pan and smooth it into the corners. Bake for about 15 minutes, or until the top springs back when lightly pressed with your finger.
Remove the cake from the oven and immediately sift confectioners sugar generously over the surface of the cake. Cover the cake with a long piece of wax paper, and then cover the wax paper with a cookie sheet. Holding them firmly together, flip the jelly-roll pan over onto the cookie sheet. Remove the pan and peel the foil off the bottom of the cake. Then roll the warm cake and the wax paper tightly together from the narrow end. Let the cake roll stand on the cookie sheet until cool.
While the cake is baking and cooling, make the glaze. Melt the chocolates and the coffee in a small saucepan over low heat. Stir until smooth. Add the butter and stir until it is melted and completely incorporated. Remove from the heat and stir in the rum. Let it cool to room temperature.
When the cake is cool, put the pan of glaze into a larger bowl of ice water and stir constantly until it thickens slightly. Reserve 1/3 cup of glaze for the top of the cake. Unroll the sponge and spread the glaze evenly to the edges of three sides of the cake; leave an inch or so unfrosted on one narrow end. Reroll the cake (without the wax paper inside this time!), and then spread the reserved glaze over the top and sides with a small spatula. Sprinkle the chocolate shavings over the glaze (you will have to gently press them into the sides), and then refrigerate the roll for 30 minutes, or until the glaze is firm.
Remove roll from the refrigerator, transfer to a serving platter, and sift confectioner's sugar generously over the top. Serve at room temperature, birthday candles optional.