Yule Log

Steps

1. Heat the oven to 350°F. Coat a 10x15-inch jelly roll pan with nonstick spray, line it with parchment and spray the paper. Whisk the flour, cocoa, baking powder and salt in a small bowl.
2. In a large bowl, beat the egg yolks, 1/2 cup of the sugar and the vanilla on high speed until thick and pale, about 3 minutes.
3. In a clean bowl with clean beaters, whip the egg whites until foamy. Slowly add the remaining 1/4 cup sugar and beat until the whites hold stiff, glossy peaks.
4. Stir a third of the whites into the yolks to loosen them. Sift the flour mixture over the top and fold it in gently, then fold in the rest of the whites until no streaks remain.
5. Spread the batter evenly in the pan and bake 12 to 14 minutes, until the center springs back when pressed lightly. Meanwhile, lay a clean kitchen towel on the counter and dust it with the 2 tablespoons powdered sugar.
6. Loosen the edges with a knife and flip the hot cake onto the towel. Peel off the parchment and roll the cake up from a short end with the towel inside. Cool it seam side down on a rack for 1 hour.
7. For the filling, whip the cream, powdered sugar and vanilla until it holds firm peaks. Keep it cold until the cake has cooled.
8. For the frosting, beat the butter until creamy. Beat in the powdered sugar, cocoa and salt on low, then add the cream and vanilla and beat on medium until fluffy, about 2 minutes.
9. Gently unroll the cake; small cracks are fine. Spread the filling over it, leaving a 1/2-inch border, then roll it back up without the towel and set it seam side down on a platter.
10. Cut a 2-inch piece off one end at a slant. Attach it to the side of the log with a dab of frosting so it looks like a branch.
11. Spread the frosting over the log and branch; leave the cut ends bare if you want the swirl to show. Drag a fork along the frosting so it looks like bark, then chill at least 1 hour.
12. Just before serving, dust with powdered sugar for snow and tuck rosemary sprigs around the base.

Good to know

• The filled and frosted log keeps, loosely covered in the fridge, for up to 2 days. Add the powdered sugar and rosemary just before serving.
• To freeze, chill the frosted log until firm, wrap it well and freeze for up to 1 month. Thaw overnight in the fridge.
• Roll the cake while it is still hot. That first roll is what keeps it from cracking later, so have the towel ready before the timer goes off.
• For a ganache coat instead of buttercream, pour 3/4 cup hot heavy cream over 8 ounces chopped semisweet chocolate, stir until smooth and let it stand at room temperature until thick enough to spread, 1 to 2 hours.