Jelly roll cake is one of those desserts that has a fantastic visually-impressive to easy-to-make ratio. Here’s a foolproof way to get that look—and taste—of soft, sweet cake delightfully swirled with jammy fruit.
Using an offset spatula, gently spread the cake batter out to an even thickness. The cake bakes and sets up quickly, so it’s important to make the batter as level as possible in the pan before it goes into the oven.
Immediately after removing the cake from the oven, run a knife around the edge of the cake and flip it out onto a large sheet of fresh greased parchment, then peel off and discard the parchment paper that has baked onto the cake. It is important to remove the cake from the pan and prepare it for rolling while still hot, otherwise the cake will crack when it is filled and rolled.
Turn the cake so the short side is facing you. Starting from the short side, roll the cake and fresh parchment into a log. Let the cake cool seam side down for 15 minutes. Rolling the warm cake helps “train” it so that it will roll easily after it’s cooled and spread with jam.
Unroll the cake. Spread the jam over the surface of the cake, leaving a ½-inch border at the edges. If you spread the filling to the edge, it will leak out the ends when you roll it up again.
Reroll the cake gently but snugly around the jam, leaving the parchment behind as you roll.
Trim thin slices off the ragged-looking ends of the cake. Transfer the cake to a platter, cool to room temperature, and dust with confectioners’ sugar just before serving. If you dust the confectioners’ sugar over the cake too early, the sugar will “melt” into the cake.