Chocolate Peppermint Swiss Roll

Ingredients

• 1/3 cup all-purpose flour
• 1/4 cup unsweetened cocoa powder, plus extra for rolling the cake
• 1/8 teaspoon kosher salt
• 6 large eggs
• 2/3 cup sugar
• 1 teaspoon vanilla extract
• 4 tablespoons unsalted butter, melted and cooled, but still liquid
• 1 1/4 cups heavy whipping cream
• 2 tablespoons sugar
• 1 teaspoon peppermint extract
• 1/2 cup heavy cream
• 4 ounces bittersweet chocolate, chopped, divided
• 1 teaspoon light corn syrup
• 1/4 cup crushed peppermint candies or candy canes
• Standard half-sheet pan or baking sheet with a rim
• Offset spatula

Directions

1. Heat the oven to 450F, with a rack placed in the middle. Coat a 13 x 17-inch rimmed baking sheet with cooking spray, cover the bottom with parchment paper, spray the parchment, and dust the pan with cocoa powder, shaking away the extra. Put the pan aside. Sift the flour, cocoa powder, and salt together for the cake, then set that mixture aside as well. To warm the eggs and sugar, pour 2 inches of water into a medium saucepan and bring it to a gentle simmer over medium heat. In the bowl of a stand mixer, or in another large heatproof bowl, combine the eggs, sugar, and vanilla extract. Rest the bowl over the simmering water, making sure the bowl is wider than the saucepan and does not touch the water.
2. Whisk the eggs, sugar, and vanilla extract steadily with a sturdy whisk until the mixture feels warm, looks pale, and the sugar has dissolved. Take the bowl off the heat. With a stand mixer fitted with the whisk attachment, or with a hand mixer, whip the egg mixture on high speed until it is glossy, very pale, and almost tripled in volume, about 5 to 10 minutes depending on your mixer.
3. Add the dry mixture in two additions. Scatter half over the whipped eggs and fold gently until it is only just incorporated. Add the rest over the batter and continue folding until the batter looks even and no dry streaks remain.
4. Pour in the melted, cooled butter and stir it through the batter.
5. Move quickly now: spoon the batter onto the prepared baking sheet and use an offset spatula to smooth it into an even layer.
6. Bake for 6 to 7 minutes, until the cake springs back when touched and has started to come away from the edges of the pan. Let the cake cool for 2 to 3 minutes, but do not leave it longer.
7. As the cake bakes, get the towel ready for rolling. Choose a clean kitchen towel larger than the baking sheet, or overlap two if needed, and coat the surface with cocoa powder.
8. To roll the cake, work quickly and confidently. Loosen the cake from the sides of the pan with a knife, turn the pan on its side, and invert it onto the cocoa-dusted towel. Lift off the pan carefully, then peel away the parchment. Bring the towel over one short end of the cake and gently roll the cake up inside it. Transfer the rolled cake to a wire rack and let it cool completely, an hour or longer.
9. For the filling, whip the heavy cream until it becomes soft and billowy. Add the sugar and peppermint extract, then keep whipping until the cream just holds firm peaks. Stop before it gets overwhipped.
10. Carefully unroll the cake on a clean surface. Spread the whipped cream filling evenly over it, leaving a 1-inch border around the edges. Roll the cake up again, this time leaving the towel behind. If some of the whipped cream slips out while you roll, scoop it up and tuck it back in.
11. Wrap the cake roll first in parchment, then in plastic wrap. Refrigerate it for at least 30 minutes so it can set, or chill it as long as overnight.
12. When you are ready to finish the cake, prepare the ganache. Add 2 inches of water to a medium saucepan and bring it to a gentle simmer over medium heat. Place a larger bowl over the saucepan, above the water. Put the heavy cream, two-thirds of the chopped chocolate, and a pinch salt into the bowl, and stir until the chocolate melts. Take the bowl off the heat, then stir in the remaining chocolate and the corn syrup.
13. Unwrap the chilled cake and place it seam-side down on a platter. Tuck two pieces of parchment along the sides of the log to catch any drips. Pour the ganache over the cake until it is fully coated. Pull away the parchment drip catchers, then sprinkle the crushed peppermint candy over the top.
14. Refrigerate the cake for 20 minutes. Slice and serve.