Chocolate Swiss Rolls are one of those desserts that combine elegance with indulgence. A tender, cocoa-infused sponge cake, rolled around a luscious cream filling, creates a treat that looks as stunning as it tastes. This recipe takes inspiration from classic European pastry traditions, using a pionono sponge (a light and flexible cake layer) and a rich German buttercream flavored with chocolate. The result? A soft, melt-in-your-mouth roll with a creamy, dreamy filling — perfect for holidays, birthdays, or whenever you want to impress.
Ingredients
For the Pionono Sponge
6 large eggs
60 g sugar (about ⅓ cup)
1 tbsp vanilla essence (or vanilla bean paste for deeper flavor)
40 g all-purpose flour (about ⅓ cup)
20 g bitter cocoa powder (about 3 tbsp, unsweetened)
1 tbsp honey
½ tbsp fine salt (a small pinch enhances flavor)
For the German Buttercream Filling
500 ml whole milk (2 cups)
120 g sugar (about ½ cup + 2 tbsp)
40 g cornstarch (about ⅓ cup)
100 g egg yolks (about 5 large yolks)
Vanilla to taste (½ tsp extract or 1 vanilla bean)
70 g cocoa powder (about ¾ cup)
660 g unsalted butter (room temperature, about 3 cups)
Optional Garnishes
Whipped cream rosettes
Shaved chocolate or cocoa dusting
Toasted walnuts or hazelnuts
Chocolate curls or sprinkles
Step-by-Step Instructions
Step 1: Make the Pionono Sponge
The pionono is a thin, flexible sponge cake, similar to a génoise but designed specifically for rolling without cracking.
Whip the eggs & sugar: In a large bowl, beat the eggs, sugar, and honey with an electric mixer at medium-high speed until the mixture is thick, pale, and has doubled in volume. This step is crucial for incorporating air, as the cake relies on whipped eggs rather than baking powder for lift.
Add flavorings: Mix in the vanilla essence and salt.
Sift and fold: Sift together the flour and cocoa powder to remove lumps. With the mixer on low speed (or using a spatula), gently fold into the egg mixture until just incorporated. Avoid overmixing, as this can deflate the batter.
Prepare the pan: Line a 50 x 30 cm (20 x 12 inch) jelly roll or sheet pan with parchment paper and lightly butter it. Spread the batter evenly across the surface using an offset spatula.
Bake: Bake at 190–200°C (375–390°F) for 8–10 minutes, or until the sponge is just set and springs back lightly when touched. Do not overbake; otherwise, the sponge may crack when rolled.
Prepare for rolling: Dust a clean sheet of parchment paper with powdered sugar. As soon as the sponge is baked, turn it out onto this paper and carefully peel off the original parchment. While still warm, roll the cake up gently (with the new paper inside). Wrap in plastic film and refrigerate for at least 30 minutes. This step “trains” the cake to hold its rolled shape.
Step 2: Make the German Buttercream Filling
Unlike American buttercream, which is simply butter and sugar, or Swiss buttercream, which uses meringue, German buttercream is made by enriching pastry cream with butter. The result is smooth, rich, and less sweet, making it perfect for rolled cakes.
Cook the pastry cream: In a saucepan, whisk together milk, sugar, cornstarch, egg yolks, and cocoa powder until smooth. Place over medium heat and cook, whisking constantly, until thickened and bubbling. The mixture should coat the back of a spoon.
Cool completely: Transfer the pastry cream to a bowl, cover with plastic wrap pressed directly against the surface (to prevent a skin), and let it cool to room temperature.
Cream the butter: In a stand mixer fitted with a paddle attachment, beat the softened butter until pale and fluffy.
Combine: Gradually add the cooled pastry cream to the butter, beating until smooth and fully incorporated. If desired, add extra cocoa powder at this stage for a more intense chocolate flavor.
Step 3: Assemble the Roll
Unroll the sponge: Carefully unroll the cooled pionono sponge. If it cracks slightly, don’t worry — the filling and final decoration will disguise imperfections.
Spread the filling: Using an offset spatula, spread an even layer of the German buttercream across the surface of the sponge, leaving about 1 cm (½ inch) border around the edges to prevent overflow.
Optional add-ins: For added texture, sprinkle toasted chopped walnuts, hazelnuts, or even chocolate chips over the buttercream.
Roll it up: Starting from the short edge, gently but firmly roll the cake into a log. Use the parchment paper underneath to help guide and tighten the roll without tearing the sponge.
Chill: Wrap the rolled cake tightly in plastic film and refrigerate for at least 1 hour. This helps the roll set and makes it easier to slice neatly.
Step 4: Decoration
Once chilled, trim the ends of the roll with a sharp knife for a clean finish. Decorate as you like:
Pipe rosettes of whipped cream or extra buttercream on top.
Dust lightly with cocoa powder or powdered sugar.
Add chocolate curls or shavings for an elegant look.
Garnish with chopped pistachios or hazelnuts for contrast.
Tips for Success
Egg Volume = Sponge Texture – The air whipped into the eggs is what gives the sponge its structure. Beat thoroughly until pale and fluffy.
Don’t Overbake – Even 1–2 extra minutes in the oven can dry out the pionono, making it prone to cracking.
Roll While Warm – Rolling the cake immediately after baking (with parchment) ensures flexibility.
Chill Before Cutting – Cold rolls slice beautifully, while warm ones can squish and lose shape.
Make Ahead – The sponge can be baked a day in advance and stored rolled in plastic. The finished roll keeps well refrigerated for 3–4 days.
Serving Suggestions
Slice into 2–3 cm rounds for a beautiful tea-time presentation.
Serve with fresh berries and whipped cream for contrast.
Drizzle with chocolate sauce for extra indulgence.
Variations
Classic Vanilla Roll: Omit cocoa and make a plain pionono filled with vanilla buttercream.
Mocha Roll: Add espresso powder to both the sponge and buttercream for a coffee-chocolate twist.
Holiday Yule Log: Decorate with chocolate ganache and meringue mushrooms to turn this into a festive Bûche de Noël.
Nutella Roll: Swap buttercream for Nutella whipped with cream for a quick alternative.
Storage
Store wrapped in plastic film in the refrigerator for up to 4 days.
Bring to room temperature for 15 minutes before serving for the best texture.
Can be frozen (without decoration) for up to 1 month. Defrost overnight in the fridge before serving.
✨ Final Thoughts
This Chocolate Swiss Roll with German Buttercream is the perfect marriage of light, airy sponge and rich, creamy filling. Unlike heavier cakes, it feels delicate and refined, yet it delivers all the chocolate satisfaction you crave. Once you master the pionono technique, you can customize the filling endlessly — making this a versatile recipe you’ll return to again and again.
One bite, and you’ll understand why this classic dessert has stood the test of time!