I found a recipe online, since it was not in any cookbooks I have, and I altered it a little as well as followed others' comments about the best way to make it. The version I found used flourless chocolate cake, which makes it a lot harder to create a fluffy cake, since there are no leavening ingredients.
This is the recipe I used, and I added my comments at certain steps.
Ingredients:
Mousse--
2 cups heavy cream
1/2 cup confectioner's sugar
1/2 cup unsweetened cocoa powder
1 teaspoon vanilla extract
Cake--
6 egg yolks
1/2 cup white sugar
1/3 cup unsweetened cocoa powder
1 1/2 teaspoons vanilla extract
1/8 teaspoon salt
6 egg whites
1/4 cup white sugar
confectioner's sugar for dusting
- Preheat oven to 375 degrees F (190 degrees C). Line a 10x15 inch jellyroll pan with parchment paper. (The parchment paper needs to be sprayed with Pam or something similar, otherwise it will be impossible to peel off of the cake.) In a large bowl, whip cream, 1/2 cup confectioners' sugar, 1/2 cup cocoa, and 1 teaspoon vanilla until thick and stiff. Refrigerate.
- In a large bowl, use an electric mixer to beat egg yolks with 1/2 cup sugar until thick and pale. (This will take at least 5 minutes with the mixer on the highest speed. The egg yolk mixture will be very thick and have almost no color.)Blend in 1/3 cup cocoa, 1 1/2 teaspoons vanilla, and salt. In large glass bowl, using clean beaters, whip egg whites to soft peaks. Gradually add 1/4 cup sugar, and beat until whites form stiff peaks. Immediately fold the yolk mixture into the whites. Spread the batter evenly into the prepared pan.
- Bake for 12 to 15 minutes in the preheated oven, or until the cake springs back when lightly touched. Dust a clean dishtowel with confectioners' sugar. Run a knife around the edge of the pan, and turn the warm cake out onto the towel. Remove and discard parchment paper. Starting at the short edge of the cake, roll the cake up with the towel. (Be very careful when doing this, because the cake could tear.) Cool for 30 minutes.
- Unroll the cake, and spread the filling to within 1 inch of the edge. Roll the cake up with the filling inside. Place seam side down onto a serving plate, and refrigerate until serving. Dust with confectioners' sugar before serving. (I actually spread the remaining mousse mixture on the outside of the cake, and then I dragged a fork through it to make it look like bark. Most pictures I found of this kind of cake looked like that.)
The finished product.
A view of the layers inside.