Yule Log Cake (Bûche de Noël)

Step 1

Preheat oven to 350°F, grease a 10x15-inch jelly roll pan, and line with parchment paper.

Step 2

In a bowl, whisk together the flour, cocoa powder, and salt; set aside.

Step 3

In a large bowl, beat the egg yolks with half the sugar until pale and thick, about 3 minutes.

Step 4

In a separate clean bowl, beat the egg whites to soft peaks, then gradually add the remaining sugar and beat to stiff, glossy peaks.

Step 5

Fold the flour mixture into the egg yolk mixture, then gently fold in the beaten egg whites in two additions until just combined.

Step 6

Spread the batter evenly in the prepared pan and bake for 10-12 minutes until the cake springs back when touched.

Step 7

Turn the warm cake out onto a clean kitchen towel dusted with cocoa powder, peel off the parchment, and roll the cake up in the towel from the short end; let cool completely, about 30 minutes.

Step 8

Meanwhile, heat 1/2 cup of the heavy cream in a saucepan until just simmering, then pour over the chopped dark chocolate and let sit for 2 minutes before stirring until smooth to make the ganache; let cool to a spreadable consistency, about 20 minutes.

Step 9

Whip the remaining heavy cream with the softened butter until soft peaks form to make the filling.

Step 10

Unroll the cooled cake, spread the whipped cream filling evenly over the surface, and roll the cake back up without the towel.

Step 11

Place the cake seam-side down on a serving platter and spread the ganache over the outside.

Step 12

Use a fork to drag lines through the ganache to resemble tree bark.

Step 13

Chill for at least 1 hour before slicing and serving.