Preheat oven to 350°F (180°C). Spray a 17¼x12¼-inch rimmed baking sheet with baking spray with flour. Line bottom of pan with parchment paper; spray parchment.

In the bowl of a stand mixer fitted with the whisk attachment, beat eggs and granulated sugar at high speed until thick, pale, and ribbon-consistency, 5 to 7 minutes. Sift flour, cocoa, baking powder, and salt onto egg mixture. Gently fold with a balloon whisk until combined.

In a medium bowl, whisk together oil, buttermilk, food coloring, vanilla, and vinegar; add 1 cup (75 grams) egg mixture, and stir until combined. Fold oil mixture into remaining egg mixture until combined, scraping bottom of bowl. Pour batter into prepared pan, spreading smooth with an offset spatula.

Bake until set and top springs back when gently touched, 15 to 18 minutes. Let cool completely in pan on a wire rack.

Loosen cooled cake from sides of pan if needed. Using a serrated knife, trim ½ inch of each short side of cake. Cut cake into 4 (12x4-inch) pieces, being sure to cut through the parchment as well; use scissors if needed. Carefully remove each cake piece, with parchment attached, from pan. Spread ⅔ cup (115 grams) Cream Cheese Filling onto each cake piece.

Starting with one short side, roll up 1 cake piece into a log, removing parchment as you roll, and place vertically in center of a cake plate. Carefully wrap a second cake piece around center roll, removing parchment as you roll. Repeat with remaining cake pieces, creating a spiral. Cover and refrigerate until firm, about 4 hours.

Spoon Swiss Meringue into a pastry bag fitted with a medium open star piping tip (Ateco #824). Starting at base of cake, pipe meringue vertically up side of cake. Repeat all around cake, occasionally piping small circles to resemble the knots of a tree. Pipe a spiral on top of cake, covering ends of vertical lines as you reach outer edge. Using a handheld kitchen torch, carefully toast meringue as desired.

Decorate with Meringue Oyster Mushrooms, Almond-Chocolate Pine Cones, Sugared Cranberries and Rosemary, and confectioners’ sugar as desired. Best served same day as made and assembled. Refrigerate in an airtight container for up to 3 days.