Raspberry White Chocolate Bûche de Noël

1. Preheat the oven to 400°F. Grease a jelly roll pan (or a 10½-inch-by-15½-inch baking sheet) with nonstick spray and line it with parchment paper, leaving 1 inch of overhang on each end. Grease the parchment with more nonstick spray.

2. Make the Cake: In a small bowl, whisk the cake flour, all-purpose flour and salt to combine.

3. In the bowl of an electric mixer fitted with the whisk attachment, whisk the eggs and egg yolks on medium speed until pale yellow and lightened in texture, about 2 minutes. Gradually add ½ cup (99g) granulated sugar and continue to whip at medium-high speed until very light, about 5 minutes. Transfer the mixture to a medium bowl. Clean the bowl thoroughly before beginning step 4. (This is important: Any fat left in the bowl from the egg yolks can ruin the meringue.)

4. In the bowl of an electric mixer fitted with the whisk attachment, whisk the egg whites and cream of tartar on medium speed until they become foamy, about 2 minutes. Add the sugar in a slow, steady stream and continue to whisk on medium-high speed until the meringue reaches medium peaks, about 3 minutes more. Add the vanilla and mix to combine.

5. Sprinkle half the flour mixture over the egg yolk mixture and, using a silicone spatula, fold in gently to combine. Sprinkle the remaining flour over the mixture and repeat.

6. Add about a quarter of the meringue to the batter and mix to incorporate. (You can mix more vigorously to combine here—it helps to temper the batter and make the remaining meringue easier to incorporate.) Gently fold in the remaining meringue in two or three additions, folding very gently only until fully incorporated. Do not overmix. Pour the batter into the prepared pan and spread into an even layer, working quickly so as to not deflate the batter. Transfer to the oven and bake until the edges just begin to turn golden and the center springs back gently when touched in the center, 7 to 9 minutes.

7. While the cake bakes, scoop some confectioners’ sugar into a fine-mesh sieve and set it on a plate. Line your work surface with a large piece of parchment paper.

8. As soon as the cake comes out of the oven, dust the work surface evenly with confectioners’ sugar. Use an offset spatula to loosen the cake from the edges of the pan. Use the parchment overhang to lift the cake out of the pan and invert it onto the sugared work surface. Carefully peel away the parchment from the cake. With one of the long sides of the cake facing you, use the underlying sheet of parchment to roll it into a tight cylinder. Let the cake cool completely, rolled up.

9. Make the Fillings: In a small saucepan, combine the raspberries and sugar; heat over medium-low heat, stirring occasionally until the berries soften completely and break down, 7 to 9 minutes. Mash the berries with a fork, then strain the mixture through a sieve, collecting the juice and discarding the solids. Cool for about 5 minutes.

10. In the bowl of an electric mixer fitted with the paddle attachment, cream the butter, cream cheese and white chocolate until well combined, about 2 minutes. Add the confectioners’ sugar, vanilla and salt; mix to combine.

11. Transfer half the frosting into a pastry bag or large zip-top bag. Add the cooled raspberry juice to the remaining filling and mix to combine. Refrigerate this mixture for 5 to 10 minutes to firm up slightly, then transfer it to another pastry bag. Cut 1-inch openings at the end of each bag.

12. Unroll the cake and position it on the parchment paper with one of the long sides facing you. Starting at the far end, pipe a 1-inch stripe horizontally across the top of the cake. Pipe another 1-inch stripe below it with the pink frosting. Repeat, working your way down the cake and alternating colors as you pipe. Use a small offset spatula to spread the mixture back and forth a few times to even out any spots and to lightly blend the two fillings together.

13. Starting with the long side closest to you, gently roll up the cake into a log. The log won’t be as tight this time because of the filling, but try to keep it as round as possible. (Use the paper to help you. It adds a protective layer that allows you to apply a bit of pressure as you wrap without damaging the cake.) Chill the roll while you prepare the remainder of the recipe (or up to overnight).

14. When the cake is chilled, remove it from the parchment and transfer to a cutting board. Use a serrated knife to gently trim the ends by ½ inch. Cut a 2½-inch-wide piece from one side. Transfer the large log to a serving platter, spread a small amount of melted white chocolate on one of the cut ends of the smaller piece, then place it on top of one side of the log. Return to the fridge to chill.

15. Make the Meringue: Preheat the oven to 275°F and line a baking sheet with parchment paper. Bring a medium saucepan with about 2 inches of water to a simmer over medium-low heat. In a medium heat-safe bowl, whisk the egg whites, sugar, salt and vanilla to combine, then place the bowl on top of the saucepan.

16. Heat the mixture, whisking constantly, until it reaches 160°F on a thermometer. Transfer the heated mixture to the bowl of an electric mixer fitted with the whisk attachment (or use a handheld electric mixer). Whisk the mixture on medium-high speed until it reaches medium peaks, about 5 minutes. Transfer a quarter of the meringue to a disposable pastry bag fitted with a medium round tip.

17. Make the Mushrooms: Pipe 10 to 15 mushroom caps (rounds of meringue) and 20 to 25 stems (sticks of meringue) onto the prepared baking sheet. Transfer to the oven and lower the temperature to 250°F. Bake until the meringue is dry and crisp, about 1 hour. Cool completely.

18. While the meringue mushrooms bake, dollop the remaining meringue over the chilled cake and spread evenly to coat. Use a small spatula to create bark-like ridges, working across the length of the log. Use a kitchen torch to gently toast the meringue, if desired.

19. Use the remaining melted white chocolate to attach the meringue mushroom caps to their stems by dipping one end of the stem into the chocolate then pressing into the base of the meringue cap. Do the same with the extra stems, using the raspberries as mushroom caps. Sprinkle the crushed freeze-dried raspberries over the surface of the meringue mushrooms, if using. Decorate the log with the mushrooms. Serve immediately.