S'mores Buche de Noel

Directions

1. Preheat oven to 400F. Grease a 9"x13" pan, then line with greased parchment paper.
2. In the bowl of a stand mixer, beat egg whites until foamy. Slowly pour in 2 tablespoons of the sugar, then whip until soft peaks form. Whip by hand (this gives you more control) until the whites reach stiff peaks. You could do this with the stand mixer, but be very careful.
3. In another bowl, combine the remaining 2 tablespoons of the sugar, the honey, egg yolks, and vanilla. Whip in a stand mixer until the mixture is light and fluffy and almost triples in volume. Fold in the egg whites, one third at a time, until almost fully incorporated (just a few small streaks remain). Then sift in the two flours and 1/2 teaspoon salt, then fold until fully incorporated.
4. Pour the batter into the greased pan, smoothing the top with a knife or spatula. Bake for 7-8 minutes, or until it bounces back when touched or a toothpick inserted in the center comes out clean. Do not overbake.
5. Immediately out of the oven, sift cocoa powder on the top of the cake just until covered, then invert onto a towel laid on the counter. Press down on the cake with the pan to flatten the original top, then remove the parchment paper and sift with cocoa powder. Starting with one of the shorter sides, roll the cake gently, along with the towel. Leave on a wire rack, seam side down, to cool completely.
6. To make the ganache, place a glass bowl over a pot of simmering water over medium heat. Make sure the bowl does not touch the water. Add to the bowl 1/2 teaspoon salt, the cream, and the egg yolks. Whisk to smooth, then cook, stirring constantly, until thick enough to coat the back of a spoon, about 10 minutes. Remove from heat and add the chocolate, stirring until fully melted. If the filling is not sweet enough for you, add sugar to taste and stir to dissolve. If the sugar does not dissolve, place back on the pot of water until smooth. Let cool until it thickens into a more viscous consistency.
7. To make the marshmallow frosting, combine the egg whites, cream of tartar, salt, 1 1/2 cups sugar, and vanilla in the bowl of a stand mixer set atop a pot of simmering water on medium heat. Whisk until the sugar is fully dissolved. If whipping by hand, whip until soft peaks form, then remove from heat and whip until stiff peaks form. Alternatively, to whip with a stand mixer, keep whisking the egg whites after the sugar has dissolved until they are very liquidy and starting to foam. Attach bowl to stand mixer and whip to just below stiff peaks.
8. To make the candy flames, preheat the oven to 375F. Line a baking sheet with ungreased parchment paper. Divide the remaining 1/2 cup of sugar into three portions. Add the red and yellow food colorings to create a red, an orange, and a yellow sugar mixture. It's okay if the sugar is a bit lumpy. Arrange the sugar on the parchment paper, starting with a blob of yellow, then crowned with orange and finally topped red to look like a flat flame. Leave about an inch of space between the candy flames, and make as many as the amount of sugar allows or as many as you can fit. Melt the sugar in the oven--be careful, this can happen very quickly, and you don't want the sugar to burn. You may have to take some of the flames out before the others due to variations in size and oven temperature. When the flames are ready, the sugar will have melted and will turn into a glossy, glass-like sheet. This may take anywhere from 30 seconds to 3 minutes, depending on your oven and the thickness of the sugar coats. Let cool on the parchment, then carefully peel off. Set aside to cool completely.
9. To assemble the cake, unroll the cooled cake. Spread the filling all over, leaving about one inch uncovered at the end. Reroll the cake, this time without the towel, and transfer to a plate. Cut the cake from one end on a shallow diagonal, then cut again from the new end to make a straight cut once again. Using some of the frosting as "glue," attach one piece to the top and the other to the side, with their diagonal cuts on the cake. Make sure the two pieces "point" in the same direction. Use the remaining frosting to cover all of the cake except for the cut ends. Texture the cake with swooshes to achieve a more woody appearance. Using a blowtorch on the lowest setting, torch the frosting until most of it is toasted and the peaks are a deep brown. Attach the candy flames all along the log.