Chocolate roulade is a type of dessert that consists of a thin sponge cake covered in a whipped frosting, ganache or other filling and then tightly rolled into a cylindrical shape so the coating becomes a spiral filling inside the cake. There are many recipes for the cake, but the classic chocolate roulade recipe involves no flour, instead using only eggs and sugar for the cake. The filling can be nearly anything from basic whipped cream to chocolate mousse or fruits and jams. Variations of the chocolate roulade exist in several areas, including Germany, Central Europe and Hong Kong.
The flourless chocolate roulade batter begins by whipping the whites and yolks of eggs separately. The sugar for the cake is whipped into the yolks along with any other flavorings, such as vanilla. Once the whites have been whipped to stiff peaks, they are folded into the yolks. Cocoa powder is then folded in to complete the batter. Some recipes call for the use of bittersweet or dark chocolate instead of, or in addition to, the cocoa powder.
The batter is poured into a sheet pan that has been lined with buttered or greased parchment paper and then baked in an oven until it rises. After the cake has completed cooking, it is left to cool completely, sometimes overnight. While the cake is cooling, sugar and water are heated to form a simple syrup. The syrup is usually flavored with a liqueur, rum or another type of alcohol that has some taste. The completed syrup is poured on the cool cake to make it moist and easier to roll.
The filling for the chocolate roulade can be nearly anything, but whipped cream and chocolate ganache are two traditional types of filling. A simple whipped cream with sugar and a little vanilla can help the chocolate flavor of the cake. A chocolate ganache, which is chocolate that has been melted in a double boiler and then mixed with cream, can intensify the sweet chocolate flavor of the roulade.
The final steps in creating a chocolate roulade begin with spreading the filling in an even coat on the flat cake. The cake is then rolled tightly from one end to the other with the filling on the inside. The syrup should help the flexibility of the cake, but it is not uncommon for the roll to crack in certain places during the process. The rolled cake is transferred to the final serving platter and then refrigerated until it has set and is firm.
Chocolate roulade can be served dusted with powdered sugar or covered in frosting or whipped cream. Chocolate shavings can be applied to the outside to give the appearance of tree bark, as is traditional when making a Yule log for Christmas. Fresh fruits, melted chocolate or more ganache also can be poured over the top of the cake for a more dramatic presentation.