Bûche de Noël (Chocolate Yule Log)

Before you start

A bûche de Noël is a rolled sponge cake dressed up to look like a log on a holiday table. This version uses a cocoa sponge for flavor and color, a mascarpone whipped cream that holds its shape after slicing, and a chocolate ganache spread on thickly and dragged with a fork to look like bark.

Plan it across a few stages. The ganache needs time to firm to a spreadable consistency, the sponge must be rolled while warm and cooled in its towel, and the filled roll needs a chill before you can cut the stump and frost it. None of these steps is difficult, but rushing them is how logs crack, slump or slide.

Ingredients

• Ganache bark170 g (6 oz) dark chocolate, 60 to 70% cacao — finely chopped
• 180 ml (¾ cup) heavy cream
• 15 g (1 tbsp) unsalted butter — soft
• Cocoa sponge4 large eggs — room temperature
• 100 g (½ cup) granulated sugar
• 50 g (⅓ cup + 1 tbsp) all-purpose flour
• 25 g (⅓ cup) Dutch-process cocoa powder — plus more for the towel
• ⅛ tsp fine salt
• 20 g (1½ tbsp) unsalted butter — melted
• Mascarpone cream115 g (½ cup) mascarpone — cold
• 240 ml (1 cup) cold heavy cream
• 40 g (⅓ cup) powdered sugar — plus more for snow
• 1 tsp vanilla extract

Method

1. Make the ganache: bring the cream just to a simmer and pour it over the chocolate. Wait 2 minutes, then stir from the center until glossy. Stir in the butter. Leave it at cool room temperature for 1 to 2 hours, until it has the texture of soft frosting.
2. Heat the oven to 190°C (375°F). Grease and line the pan with parchment. Dust the towel evenly with cocoa powder. Sift the flour, cocoa and salt together.
3. Whip the eggs and sugar on high speed for 7 to 8 minutes, until thick, pale and holding a ribbon. Sift in the cocoa mixture in two additions and fold gently. Fold a scoop of batter into the melted butter, then fold that back into the batter.
4. Spread the batter evenly in the pan. Bake for 9 to 11 minutes, until the top springs back and the edges just pull away. Flip onto the cocoa-dusted towel, peel off the parchment and roll up from a short end with the towel inside. Cool seam side down for about 40 minutes.
5. Beat the mascarpone, cream, powdered sugar and vanilla together to firm peaks. Do not overbeat or the mascarpone turns grainy.
6. Unroll the sponge, spread the cream to within 2 cm (¾ in) of the far edge and roll it up snugly. Wrap and chill seam side down for at least 30 minutes.
7. Trim both ends. Cut a 6 cm (2½ in) piece off one end at a sharp diagonal. Set the log on a board and attach the cut piece to the side, angled face against the log, to form a branch stump. A dab of ganache holds it.
8. Spread the ganache over the log and stump, leaving the cut ends bare to show the spiral. Drag a fork along the length to make bark lines and swirl rings on the ends. Chill for 30 minutes, then dust lightly with powdered sugar just before serving.

Tips for success

• If the ganache gets too firm, warm it for 5 seconds in the microwave and stir; if too soft, chill it for 10 minutes and stir again.
• Small cracks in the sponge do not matter. The ganache covers them completely.
• Use a hot, dry knife for clean slices.

Substitutions

Mascarpone cream

Use 360 ml stabilized whipped cream or a coffee buttercream. Buttercream gives a richer, firmer log that tolerates a warm room better.

Dark chocolate ganache

Milk chocolate ganache is sweeter and softer; use 170 g milk chocolate with 120 ml cream so it still sets.

Dutch-process cocoa

Natural cocoa works here because the sponge relies on eggs, not baking soda. The color is lighter and redder.

Variations

Chestnut filling

Fold 120 g sweetened chestnut cream into the whipped filling in place of half the powdered sugar.

Meringue mushrooms

Pipe small domes and stems of Swiss meringue, dry them at 95°C (200°F) for about 1½ hours, then join them with melted chocolate and dust with cocoa.

Troubleshooting

Ganache is too runny to make bark

It needs more time to cool. Leave it at room temperature and stir every 20 minutes, or chill briefly. Do not whip it warm.

Log flattened under the frosting

The filled roll was not chilled or the cream was too soft. Chill the roll until firm and whip the filling to firm peaks.

Grainy filling

The mascarpone was overbeaten. Fold in a few spoonfuls of unwhipped cream by hand to smooth it.

Storage

Keep the finished log covered in the refrigerator for up to 3 days. Take it out about 20 minutes before serving so the ganache softens slightly, and do not leave it out longer than 2 hours.

Safety notes

Raw batter contains raw egg and flour and should not be tasted. Contains wheat, egg and milk; check chocolate labels for nuts or soy if needed.