Chocolate Yule Log

A chocolate yule log is a rolled sponge cake filled with chocolate mousse and frosted to look like a tree branch. It is the showpiece dessert for a festive table, with a tender crumb and silky filling that comes together in stages. The secret is rolling the warm cake while it is still pliable, then chilling it firm before frosting.

Ingredients for Chocolate Yule Log

All-purpose flour gives the sponge cake its structure. Cocoa powder and bittersweet chocolate deliver deep chocolate flavor to both the cake and the mousse filling. Eggs and egg yolks create lift and richness. Granulated sugar sweetens and helps the eggs hold air. Butter adds moisture and tenderness to the cake, then emulsifies the mousse. Vanilla extract rounds out the chocolate taste. Salt brightens the cocoa. Heavy cream whips into the mousse for a light, airy texture. Powdered sugar sweetens the frosting without adding grittiness.

Why This Chocolate Yule Log Works

The cake itself is a thin chocolate sponge that bakes in a shallow sheet pan. It stays moist and flexible long enough to roll while still warm, before it sets and cracks. The key is not overbaking: the cake should feel just set on top but still give slightly when you touch it.

The mousse filling is made by melting chocolate with butter, then folding in whipped cream and whipped egg whites. This creates a mousse that is both rich and airy, and it sets firm enough to hold the roll’s shape when chilled. The egg whites are raw, so pasteurized eggs are used for safety.

The frosting is a simple chocolate buttercream that stays spreadable at room temperature. Once the log is assembled and chilled, the frosting adheres well and can be textured to look like bark.

Mistakes To Avoid

Overbaking the sponge cake will make it too rigid to roll without breaking. The cake should bake only until the top feels just set and springs back lightly when touched. If it bakes much longer, it will crack as soon as you try to roll it.

Filling the log while the cake is still hot will melt the mousse and cause it to ooze out the sides. Wait until the cake has cooled to room temperature, then spread the mousse evenly, leaving a small border on all sides.

Not chilling the assembled log long enough before frosting will cause the mousse to shift and the cake to slide out of position. Four hours in the refrigerator is the minimum to set the mousse firm.

Frosting a cold log straight from the refrigerator will cause the frosting to crack and chip. Let the log sit at room temperature for 15 to 20 minutes before frosting so the surface is no longer icy.

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Ingredients

• 1 cup (120g) all-purpose flour
• 1/2 cup (50g) unsweetened cocoa powder
• 1 teaspoon baking powder
• 1/2 teaspoon salt
• 5 large eggs, separated, room temperature
• 3/4 cup (150g) granulated sugar, divided
• 1/3 cup whole milk, room temperature
• 1 teaspoon vanilla extract
• 6 ounces bittersweet chocolate, chopped
• 6 tablespoons unsalted butter
• 3 large pasteurized eggs, separated, for mousse
• 1 cup heavy cream, cold
• 2 tablespoons granulated sugar, for mousse
• 4 ounces bittersweet chocolate, chopped, for frosting
• 4 tablespoons unsalted butter, for frosting
• 2 tablespoons whole milk, for frosting
• 1/2 cup (60g) powdered sugar, for frosting
• Powdered sugar for dusting

Step-by-step Instructions

1. Preheat the oven to 375°F (190°C). Line a 15 by 10 inch jelly roll pan with parchment paper.
2. Whisk together the flour, cocoa powder, baking powder, and salt in a small bowl.
3. In a stand mixer, beat the 5 egg yolks with 1/2 cup of the granulated sugar on medium-high speed for 3 to 4 minutes until pale and thick. Mix in the milk and vanilla extract on low speed until just combined.
4. Fold the flour mixture into the egg yolk mixture in two additions, stirring gently until no streaks remain.
5. In a clean mixer bowl, beat the 5 egg whites on medium speed until soft peaks form. Gradually add the remaining 1/4 cup sugar and beat for 1 to 2 minutes more until stiff peaks form and the mixture is glossy.
6. Fold the egg white mixture into the batter in two additions, stirring gently until just combined.
7. Pour the batter into the prepared pan and spread evenly. Bake at 375°F (190°C) for 12 to 15 minutes until the top feels just set and springs back lightly when touched. Do not overbake.
8. Turn the hot cake out onto a clean kitchen towel, peel off the parchment, and immediately roll it tightly into a log with the towel. Let it cool to room temperature, about 30 minutes, then unroll it gently.
9. For the mousse, melt the 6 ounces of bittersweet chocolate and 6 tablespoons butter together over low heat, stirring until smooth. Remove from heat and let cool for 5 minutes.
10. In a clean mixer bowl, beat the 3 pasteurized egg whites on medium speed until soft peaks form. Add 2 tablespoons sugar and beat for 1 to 2 minutes more until stiff peaks form.
11. In another bowl, whip the cold heavy cream to stiff peaks.
12. Fold the cooled chocolate mixture into the egg white mixture, then fold in the whipped cream gently until just combined.
13. Spread the mousse evenly over the unrolled cake, leaving a small border on all sides. Roll the cake tightly into a log, using the towel to help guide it.
14. Place the log seam-side down on a serving plate and refrigerate for at least 4 hours until the mousse is firm.
15. For the frosting, melt the 4 ounces of bittersweet chocolate and 4 tablespoons butter together over low heat, stirring until smooth. Stir in 2 tablespoons milk, then remove from heat.
16. Stir the 1/2 cup powdered sugar into the chocolate mixture until smooth.
17. Remove the log from the refrigerator and let it sit at room temperature for 15 to 20 minutes until the surface is no longer icy.
18. Spread or pipe the frosting over the log, using a fork or small offset spatula to create a bark-like texture. Dust with powdered sugar and chill until ready to serve.