A chocolate cake roll looks like bakery work, but the trick is simple: roll the sponge up in a sugar-dusted towel while it is still warm. It cools in that shape, so when you unroll it, spread the filling and roll it again, it does not crack.
Whipped egg whites keep the cake light and springy. Fill it with whipped topping as written, or try one of the variations: ice cream for a frozen roll, berries folded into the filling, or a mocha filling with melted chocolate and a little instant coffee.
Prepare the pan. Heat the oven to 350°F. Line a 15 x 10-inch jelly roll pan with waxed paper, then grease and flour the paper and tap out the extra flour.
Mix the dry ingredients and yolks. In a medium bowl, whisk the cake flour, cocoa, cornstarch, baking soda, baking powder and salt. In another bowl, beat the egg yolks with 1/4 cup of the sugar on medium speed until pale and fluffy.
Whip the whites. With clean beaters, beat the egg whites on high until foamy. Add 1/2 cup of the sugar a little at a time and keep beating until the whites hold stiff, glossy peaks that are not dry.
Fold and bake. Fold one-third of the whites into the yolk mixture to lighten it. Fold in the rest of the whites and the flour mixture in turns, gently, just until no streaks remain. Spread the batter in the pan, smooth the top and bake until a toothpick in the center comes out clean, about 15 minutes.
Turn out the cake. Sprinkle a clean kitchen towel with the remaining 1/4 cup of sugar. Turn the hot cake out onto the towel, peel off the waxed paper and trim the crisp edges with a sharp knife.
Roll it warm. Starting from a long side, roll the cake up snugly with the towel inside. Set it seam side down on a wire rack and let it cool completely in the towel.
Fill and roll. Unroll the cooled cake and lift off the towel. Spread the whipped topping over the cake to within 1/2 inch of the edges, then roll it back up without the towel.
Serve. Set the roll seam side down on a platter and dust with confectioners’ sugar just before serving. Slice with a serrated knife.
Tips
Chill the filled roll in the freezer for about 20 minutes before slicing; it cuts much more cleanly.
Use a serrated knife and a gentle sawing motion for neat slices.
Frozen version: spread softened ice cream over the cake instead of whipped topping, roll it up, wrap well and freeze seam side down until firm. Serve with chocolate sauce.
Fold fresh berries, chopped fruit or mini chocolate chips into the filling, or swap in jam, pie filling or pudding for a sweeter cake.
For a mocha filling, fold cooled melted chocolate and a teaspoon of instant coffee granules into the whipped topping.
Questions about this recipe
Why do you roll the cake while it is warm?
A warm sponge is flexible. Rolling it in a towel while hot sets it in a curl, so it unrolls and rerolls with the filling without cracking.
My cake roll cracked. What happened?
Usually it was overbaked or rolled after it cooled. Bake just until a toothpick comes out clean, and roll it in the towel right out of the oven. Small cracks disappear under a dusting of confectioners’ sugar.
Can I use whipped cream instead of whipped topping?
Yes. Whip 1 cup of heavy cream with 2 tablespoons of confectioners’ sugar to stiff peaks. Keep the roll refrigerated and serve it within a day.
