Potato Flake Sourdough Yule Log (Bûche de Noël)

A Festive, Fermented Twist on a Classic Christmas Dessert

There’s something special about a Christmas Yule Log. The soft rolled cake, the creamy filling, the rustic “tree bark” frosting, and that charming, woodland look that is absolutely perfect for the holiday season. Thanks to a suggestion from one of my fellow bakers, this year, I wanted to take the classic Bûche de Noël and give it a potato flake sourdough spin. And what better way than by turning this dessert into a fermented one?

If you’ve ever made my Potato Flake Pumpkin Roll, you already know how beautifully potato flake sourdough transforms a simple rolled cake. It adds moisture, tenderness, and just the slightest tang that rounds out all the sweetness. This Yule Log is the winter, chocolate-rich cousin to that pumpkin roll — but even more festive and fun to decorate.

If you’ve never made a rolled cake before, don’t worry. This recipe walks you through every step in detail so your log rolls smoothly, doesn’t crack, and slices beautifully. With a little prep and creativity, you’ll have a show-stopping dessert that looks like it came from a bakery, but tastes even better because it was made right at home. 

Put on the Christmas music and make this potato flake sourdough buche de noel yule log recipe this Christmas season! Everyone will be impressed. I promise!

Traditional Yule Log?

A classic Bûche de Noël is usually a light sponge cake made with whipped egg whites, rolled up with a rich chocolate ganache filling, and decorated to look like a real log. Many traditional versions also use chocolate ganache or buttercream on the outside and sometimes even add little meringue “mushrooms” made from egg whites for a woodland touch. 

My potato flake sourdough yule log version keeps the same cozy, rustic look but uses the whole egg instead of just egg whites and uses a fermented batter for extra moisture and a light whipped cream filling for a lighter, but still rich dessert. You can easily add and swap out some of my variations with the traditional options. 

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Ingredients & Equipment

Here’s everything you need before you begin:

Equipment

• Sheet Pan (18×13-inch): Ensures even baking and creates the ideal thickness for rolling the cake.
• Stand Mixer or Hand Mixer: A stand mixer with a paddle and whisk attachment.  A hand mixer works well too if a stand mixer isn’t available.
• Large Mixing Bowl: Essential for mixing the fermented cake ingredients and combining them with the remaining ingredients.
• Fine Mesh Strainer or Sifter: Use to sift the baking soda and baking powder for a smooth, lump-free batter. Is also used to dust the final pumpkin roll with powdered sugar for a lovely finish.
• Parchment Paper: Helps the cake release easily from the pan, so you don’t risk tearing.
• Clean Kitchen Towel: Used to roll up the cake after baking. It should be lint-free to keep your cake roll neat.
• Spatula or Offset Spatula: Perfect for spreading the cream cheese frosting evenly on the cake before rolling.
• Plastic Wrap: Essential for wrapping the cake after rolling to help it set while chilling in the refrigerator.

Chocolate Cake

• 1 ¼ cups all-purpose flour (188 grams)
• ½ teaspoon instant coffee powder
• 3 Tablespoons unsweetened cocoa powder
• 1 ¼ cups sugar (276 grams)
• ¼ cup potato flake sourdough starter
• 6 eggs (about 50 g each)
• 1 teaspoon vanilla extract
• ½ cup powdered sugar (for dusting towel)

After fermentation:

• ¾ teaspoon baking soda
• ½ teaspoon salt

Whipped Cream Filling

• 2 cups heavy cream
• ½ cup powdered sugar
• 1 teaspoon vanilla

Whipped Chocolate Buttercream

• 1 cup unsalted butter, softened
• 3 cups powdered sugar
• ½ cup cocoa powder
• ¼ cup heavy cream
• 1 Tablespoon instant coffee
• ¼ teaspoon salt (omit if using salted butter)

Instructions

Mix & Ferment the Chocolate Cake Batter

In a large bowl, whisk together the flour, instant coffee, and cocoa powder. Add the sugar, potato flake starter, vanilla, and eggs. Using a hand mixer, blend until just combined — no need to whip or overmix.

Scrape down the sides of the bowl to make sure everything is fully incorporated. Cover tightly with plastic wrap and let the batter ferment at room temperature for 8–12 hours (or up to 24 hours for a deeper sour flavor). This fermentation step is what makes the cake extra tender and flavorful.

Prep & Bake

After fermentation, preheat your oven to 375°F. Spray your 18×13″ sheet pan, line with parchment paper, and spray the parchment too. (Even though parchment normally behaves, this extra spray ensures the cake releases perfectly.)

Sift the baking soda and salt evenly over the fermented batter using a fine mesh strainer. Fold lightly to combine.

Pour the batter onto your prepared sheet pan and spread it evenly. Bake for 12–15 minutes, or until the top springs back when gently pressed. Don’t overbake — that’s the #1 cause of cracking when rolling.

Roll the Cake While Warm

Before the cake comes out of the oven, lay out a clean kitchen towel and dust it generously with powdered sugar.

As soon as the cake is done, immediately flip it onto the sugar-dusted towel. Slowly peel off the parchment paper.

Starting from one long side, roll the cake up in the towel. Place seam-side down to let the cake cool fully. Doing this is the best way to “train” the cake to roll neatly later. If you roll from the short end you will get more of a swirl, but you may not have a log that is long enough to cut and position to get that yule log cake look.

Make the Whipped Cream Filling

In a stand mixer with the whisk attachment (or using handheld mixer), whip the heavy cream, powdered sugar, and vanilla. Start on low, then increase to high speed until you reach thick, sturdy, Cool-Whip-like peaks.

Avoid over-beating — stop as soon as it becomes pillowy and holds its shape.

Unroll, Fill, & Re-Roll

Once the cake is completely cool, unroll it gently. Spread the whipped cream filling all the way to the edges.

Re-roll the cake, this time without the towel. Some of the whipped topping will be coming out. That is okay, it will be the side that is on the bottom when we are done. Wrap in plastic wrap and refrigerate at least 2 hours (or overnight). This chill time helps the cake set so it slices beautifully.

Make the Whipped Chocolate Buttercream

Right before decorating, beat the softened butter for 3 minutes until creamy and pale.

Add powdered sugar, cocoa powder, heavy cream, instant coffee, and salt. Mix on low until combined, then beat on high for another 3 minutes, scraping halfway through. The frosting should be very fluffy and smooth.

Decorate Your Yule Log

For a beautiful bûche de noël look: 

Slice off about ⅓ of the cake at an angle.

Place this smaller piece against the side of the larger log to make a “branch.”

Frost the entire cake with your whipped chocolate buttercream.

Use a fork to create subtle bark-like texture.

Garnish with fresh rosemary or tarragon, and a few fresh cranberries.

Finish with a dusting of powdered sugar for “snow.”

Your log will look like it belongs on a winter woodland table. It really is like an edible Christmas decoration.

Spin-Off Idea: Potato Flake Sourdough Peppermint Mocha Roll

If you love  chocolate and mint paired together try a fun Peppermint Mocha Roll!

Try adding:

• ½ teaspoon peppermint extract to the whipped cream filling
• A bit of crushed peppermint sprinkled inside
• A dash more instant coffee in the cake to boost the mocha flavor

It’s festive, fun, and so easy to adapt without changing the base method.

Tips for Success

Choose the Right Pan

A standard 18×13″ sheet pan gives you the ideal cake thickness for rolling without cracking.

Roll While Warm

The warm roll (with powdered sugar) is what prevents cracks later. Don’t skip this step.

Don’t Overbake

Pull the cake out as soon as it springs back. Even one extra minute can make it dry.

Chill Time Helps

Refrigerating the filled potato flake sourdough yule log firms everything up for picture-perfect slices.

Use an Offset Spatula

This makes spreading both the filling and frosting easier and more even.

Storage & Make-Ahead Tips

This Yule Log is a great make-ahead dessert for busy holiday hosting.

• Refrigerator: Wrap tightly in plastic wrap and store in an airtight container for up to 1 week.
• Freeze: Freeze (before decorating) for up to 3 months. Thaw overnight in the fridge, then frost and garnish.
• Make ahead: You can bake and roll the cake one day, fill it another day, and decorate the next — it’s very flexible.

Frequently Asked Questions

My cake cracked while rolling — what happened?

Usually this means it cooled too long before rolling, or it was slightly overbaked. Small cracks can be covered with frosting, so don’t stress!

Do I have to use instant coffee?

No, but it deepens the chocolate flavor beautifully. You won’t taste the coffee itself.

Can I make this gluten-free?

I have never tired making potato flake sourdough yule logwith gluten free flours, but it might be difficult since rolled cakes are delicate. If you try it, choose a high-quality 1:1 gluten-free baking blend and let us know how it turns out!.

Can I use store-bought frosting?

Technically yes, but homemade whipped buttercream is so much more delicious and not very difficult, especially if you are going through all the steps to make this potato flake sourdough yule log from scratch anyway. 

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