Hot Chocolate Layer Cake With Marshmallow Buttercream And Chocolate Fudge Sauce

This hot chocolate layer cake is one of my favorite desserts to make when I want something rich, cozy, and memorable. I love how the soft chocolate cake layers soak up the gooey fudge sauce while the marshmallow buttercream adds a light, fluffy contrast. It feels like turning a comforting mug of hot cocoa into a celebration-worthy cake that works beautifully for winter gatherings, birthdays, or any time I want a truly indulgent treat.

Why You’ll Love This Recipe

I love this recipe because every component works together perfectly. The chocolate cake is moist and tender, the marshmallow buttercream is sweet but not overpowering, and the homemade fudge sauce adds depth and richness. I also enjoy how flexible it is, since I can prepare parts ahead of time and assemble everything when I am ready to serve.

Ingredients

(Tip: You’ll find the full list of Ingredients and measurements in the recipe card below.)

Chocolate cake layers
360 g warm coffee or hot water
360 g all-purpose flour
2 tablespoons cornstarch
300 g granulated sugar
150 g dark brown sugar
75 g unsweetened Dutch cocoa powder
1 ½ teaspoons baking powder
1 ½ teaspoons baking soda
1 ½ teaspoons salt
165 g vegetable oil
270 g sour cream, room temperature
3 large eggs, room temperature
3 teaspoons vanilla extract

Chocolate fudge sauce
50 g granulated sugar
25 g honey
60 g whole milk
100 g semi-sweet chocolate
10 g unsweetened Dutch cocoa powder
15 g unsalted butter
1 teaspoon vanilla extract
small pinch of salt

Marshmallow buttercream
400 g unsalted butter, room temperature
225 g powdered sugar
200 g marshmallow fluff
½ teaspoon vanilla paste
small pinch of salt

Directions

I begin by preheating the oven to 170°C / 340°F and lining three 20 cm (8-inch) round cake pans with parchment paper. I prepare the coffee first so it has time to cool slightly while I get everything else ready.

In a large bowl, I whisk together all the dry cake ingredients until evenly combined. In a separate bowl, I whisk together the oil, sour cream, eggs, vanilla extract, and coffee. I slowly pour the wet ingredients into the dry mixture while gently stirring, making sure the batter stays smooth.

I divide the batter evenly between the prepared pans and bake for 28 to 30 minutes, until a cake tester inserted into the center comes out clean. I let the cakes cool for a few minutes in the pans before turning them out onto a rack to cool completely.

While the cakes are baking, I prepare the fudge sauce. I heat the sugar, honey, and milk in a small saucepan over medium heat until the sugar dissolves and the milk begins to bubble. I pour this mixture over the chocolate and cocoa powder and stir until smooth. I then add the butter, vanilla extract, and salt, stirring until fully combined. I cover the surface and let it cool to room temperature.

For the marshmallow buttercream, I whip the butter until light and fluffy. I add the powdered sugar in two additions, mixing well after each one. I finish by mixing in the marshmallow fluff, vanilla paste, and salt until the buttercream is smooth and creamy.

To assemble the cake, I level the cooled cake layers. I place the first layer on a serving plate, spread a generous amount of buttercream on top, and drizzle with fudge sauce. I repeat this with the second layer, then place the final layer on top. I apply a thin crumb coat, chill the cake briefly, and then frost the entire cake with the remaining buttercream.

Servings And Timing

I usually cut this cake into 12 slices.
Preparation time is about 1 hour.
Baking time is around 28 to 30 minutes.
Total time is approximately 1 hour and 30 minutes, including cooling and assembly.

Variations

I sometimes add extra chocolate chips between the layers for even more richness. When I want a different flavor twist, I mix a little peppermint or orange extract into the buttercream. I also enjoy finishing the cake with a drizzle of extra fudge sauce on top for a more dramatic presentation.

Storage/Reheating

I store the cake covered in the refrigerator for up to 3 days. Before serving, I let it sit at room temperature for about 30 minutes so the buttercream softens and the flavors fully develop. I do not reheat this cake, as it tastes best at room temperature.

FAQs

Can I Make The Cake Layers Ahead Of Time?

I often bake the cake layers a day in advance and store them wrapped at room temperature or chilled until I am ready to assemble.

Can I Replace The Coffee In The Cake?

I replace the coffee with hot water whenever I want to avoid caffeine. The chocolate flavor still turns out rich and delicious.

How Do I Know When The Cake Is Done Baking?

I insert a cake tester or toothpick into the center of the cake. If it comes out clean, I know the cake is ready.

Can I Use Only Two Cake Pans?

I leave one-third of the batter aside while the first two layers bake, then bake the final layer once a pan is free.

Can I Freeze This Cake?

I freeze the unfrosted cake layers tightly wrapped. I thaw them at room temperature before assembling the cake.

Conclusion

This hot chocolate layer cake is a dessert I love making when I want something comforting yet impressive. The combination of moist chocolate cake, fluffy marshmallow buttercream, and rich fudge sauce makes every slice feel special. It is the kind of cake I enjoy serving to guests and savoring slowly with a warm drink on a cozy day.

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