The bûche de Noël, or "Yule log," consists of a thin sheet of silky sponge cake spread with buttercream and gently rolled into the shape of a log, jelly roll-style. It's the kind of confection that inspires obsession in a small child, or even an adult.
Chocolate coffee buttercream icing
• 3 large egg yolks
• ¼ cup sugar
• 1 teaspoon vanilla extract
• 1 cup unsalted softened butter
• 1 ounce melted, unsweetened baking chocolate
• 1 teaspoon instant coffee, prepared
Beat the egg yolks, sugar, and vanilla together. Add the chocolate and the instant coffee. Then gradually beat in the butter until the mixture is thick and stiff. Chill while you make the cake. Makes 1¼ cup—more may be required, depending on how thickly you ice the cake.
Sponge cake
• 3 large eggs
• 1 cup sugar
• 5 tablespoons water
• 1.5 teaspoon vanilla extract
• 1 cup cake flour
• ¼ teaspoon salt
• 1 teaspoon double-acting baking powder
• A mixture of 1 ounce rum, 3 ounces water, and 1 teaspoon sugar
Line a 15.5 x 10.5-inch jelly roll pan or cookie sheet, one inch deep, with a sheet of greased wax paper. Beat eggs until they have grown thick, adding the sugar gradually, then the water and vanilla all at once. Combine the salt, flour, and baking powder in a separate bowl, then add to the egg mixture. Mix just until smooth. Pour batter into the cookie sheet and cook at 375 degrees for 15 minutes or slightly less—the cake must not be too dry, or it will crack when you roll it. Test it with a wooden toothpick, and as soon as the toothpick comes out clean, remove the cake from the oven.