The Bûche de Noël or Yule log cake is a festive and classic holiday treat to prepare for Christmas.
In a large bowl, whip the cream, confectioners' sugar, cocoa, and vanilla until thick and stiff. Refrigerate until ready to use.
Preheat the oven to 375 degrees and line a 10-by-15-inch jellyroll pan with parchment paper.
In a large bowl, use an electric mixer to beat the egg yolks and sugar until thick and pale. Mix in the cocoa, vanilla, and salt.
In a separate bowl, use beaters to beat the whites until they form stiff peaks. While beating, gradually add in the sugar and cream of tartar. Fold the yolk mixture into the whites. Spread the batter evenly into the prepared pan.
Bake for 12 to 15 minutes in the preheated oven, or until the cake springs back when lightly touched. Remove the cake from the pan immediatly and turn onto a large piece of parchement paper. Remove and discard parchment paper from the back of the cake. Let the cake cool.
Spread the filling to within 1 inch of the edge. Roll the cake up with the filling inside. Place seam side down and cover in chocolate frosting. Run the prongs of a fork along the outisde to make wood-like markings. Dust with confectioners' sugar.