This towering 12 layer chocolate cake is a true celebration dessert. Featuring ultra-moist chocolate cake layers soaked with simple syrup and filled with alternating layers of silky chocolate pastry cream and rich fudgy frosting, it delivers deep chocolate flavor in every bite. Standing tall and impressive, it’s the ultimate cake for serious chocolate lovers.
Why You’ll Love This Recipe
This cake is pure chocolate indulgence balanced with thoughtful texture and flavor.
First, the cake layers are incredibly moist thanks to oil, sour cream, and the addition of water in the batter. Even without fillings, the cake is soft and tender.
Second, the alternating fillings create the perfect harmony. The chocolate pastry cream is smooth, creamy, and lightly sweet, while the fudgy frosting is thick, glossy, and intensely chocolatey. Together, they balance richness and lightness beautifully.
The simple syrup soak ensures every forkful melts in your mouth. Despite its impressive height, the cake slices cleanly and tastes balanced rather than overwhelmingly heavy.
Finally, it’s a show-stopping centerpiece. With 12 layers of cake and 12 layers of filling, this dessert is guaranteed to impress at celebrations and gatherings.
Ingredients
(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)
For the Chocolate Cake
4 cups (500 grams) all-purpose flour
4 cups (800 grams) granulated sugar
2 cups (170 grams) unsweetened cocoa powder
4 teaspoons baking soda
2 teaspoons baking powder
2 teaspoons salt
5 large eggs, at room temperature
2 cups (452 grams) sour cream or Greek yogurt, at room temperature
2 2/3 cups (630 ml) water, at room temperature
2/3 cup (160 ml) neutral oil
4 teaspoons vanilla extract
For the Simple Syrup Soak
1/2 cup (100 grams) granulated sugar
1/2 cup (120 ml) water
For the Chocolate Pastry Cream (makes about 4 cups)
2 1/4 cups (540 ml) whole milk
3/4 cup (180 ml) heavy whipping cream
1/2 cup plus 3 tablespoons (137 grams) granulated sugar, divided
1/8 teaspoon salt
6 large egg yolks
1/4 cup (32 grams) cornstarch
1/4 cup (57 grams) unsalted butter, cold and cut into pieces
4 ounces (114 grams) bittersweet chocolate, finely chopped
1 teaspoon pure vanilla extract
For the Fudgy Frosting (makes about 4 cups)
12 1/2 ounces (354 grams) bittersweet or semisweet chocolate, chopped
1 1/4 cups (300 ml) heavy whipping cream
1 1/4 cups (250 grams) granulated sugar
1/4 teaspoon salt
1/2 cup plus 2 tablespoons (142 grams) unsalted butter, softened
Preheat your oven to 350°F (180°C). Grease and line four 9-inch round cake pans with parchment paper.
In a very large bowl, sift together the flour, sugar, cocoa powder, baking soda, baking powder, and salt. Add the eggs, sour cream, water, oil, and vanilla extract. Mix with an electric mixer until smooth. The batter will be thin.
Divide the batter evenly among the four pans. Bake for about 25 minutes, or until a toothpick inserted into the center comes out clean. Let cool for 15 minutes in the pans, then invert onto wire racks to cool completely. For easier slicing, wrap and chill the cakes until firm.
To prepare the simple syrup, heat sugar and water together in a saucepan until the sugar dissolves. Let cool completely.
For the pastry cream, heat milk, cream, half the sugar, and salt until simmering. In a separate bowl, whisk egg yolks with the remaining sugar, then whisk in cornstarch. Gradually temper with the hot milk mixture, then return to the saucepan and cook until thickened. Remove from heat and stir in butter, chocolate, and vanilla. Strain, cover with plastic wrap touching the surface, and chill until set.
For the frosting, place chopped chocolate in a bowl. Heat cream, sugar, and salt until sugar dissolves and mixture simmers. Pour over chocolate and whisk until smooth. Add butter and whisk until glossy. Chill until spreadable.
Level the cooled cakes and slice each cake horizontally into three equal layers, yielding 12 layers total.
To assemble, line a 9-inch cake ring with acetate. Place the first cake layer inside and brush lightly with simple syrup. Spread a little over 1/2 cup pastry cream evenly. Top with another cake layer, brush with syrup, and spread a little over 1/2 cup frosting. Continue alternating pastry cream and frosting between cake layers, brushing each layer with syrup, until you have 6 cake layers stacked. Freeze until firm.
Repeat with remaining layers to create a second 6-layer stack. Freeze both stacks until very firm.
Remove from molds. Stack one cake on top of the other, removing any cake boards. Smooth the sides with an offset spatula. Garnish with chocolate sprinkles or curls if desired.
Allow the cake to come to room temperature before serving for the best texture.
Servings and timing
Prep time: 1 hour 30 minutes
Cook time: 40 minutes
Chilling and assembly time: 5 hours
Total time: approximately 7 hours 10 minutes
Servings: 16 to 20 generous slices
Variations
You can create a 6-layer version by halving the recipe and baking in four 6-inch pans.
For a slightly lighter flavor, use semisweet chocolate instead of bittersweet in both the pastry cream and frosting.
Add a thin layer of chocolate ganache on top for a glossy finish.
For added texture, sprinkle finely chopped toasted nuts between layers.
You can also incorporate a subtle coffee flavor by adding 1 to 2 teaspoons of instant espresso powder to the cake batter.
Storage/Reheating
Store the finished cake under a cake dome in the refrigerator for up to 1 day before serving.
Leftover slices can be kept in an airtight container in the refrigerator for up to 3 days.
For best flavor and texture, allow the cake to sit at room temperature before serving. Individual slices can be warmed in the microwave for 10 to 15 seconds to soften the frosting slightly.
FAQs
Can I make this cake in advance?
Yes. The cake layers, pastry cream, and frosting can all be made ahead. The fully assembled cake can also be frozen until needed.
Do I really need four cake pans?
No. You can bake in batches if you only have two pans. Just divide the batter evenly and reuse the pans.
Why is the cake batter so thin?
This is normal. The thin batter helps create a moist and tender crumb.
Can I skip the simple syrup?
While optional, the syrup enhances moisture and gives the cake its melt-in-the-mouth texture.
Can I use dark chocolate?
You can, but it will result in a slightly more intense and less sweet flavor.
How do I slice the cakes evenly?
Chilling the cakes first helps. Use a serrated knife or cake leveler for best results.
Can I freeze the assembled cake?
Yes. Wrap it well in plastic wrap and freeze for several days if needed. Thaw gradually before serving.
What if my frosting becomes too firm?
Let it sit at room temperature until spreadable, or gently warm it in short intervals.
How do I prevent the pastry cream from forming a skin?
Press plastic wrap directly onto the surface while chilling.
Is this cake suitable for special occasions?
Absolutely. Its height and multiple layers make it perfect for birthdays, celebrations, and gatherings.
Conclusion
This Epic 12 Layer Chocolate Cake is a true labor of love. With its moist chocolate layers, silky pastry cream, and rich fudgy frosting, it delivers unmatched chocolate flavor and an unforgettable texture. Though it requires time and care, the result is a stunning dessert that will delight any chocolate lover and turn any celebration into something extraordinary.
A towering and indulgent 12 layer chocolate cake made with ultra-moist cocoa cake layers soaked in simple syrup and filled with alternating layers of silky chocolate pastry cream and rich fudgy frosting. A true show-stopping dessert for serious chocolate lovers.
Ingredients
Chocolate Cake: 4 cups (500 g) all-purpose flour
4 cups (800 g) granulated sugar
2 cups (170 g) unsweetened cocoa powder
4 teaspoons baking soda
2 teaspoons baking powder
2 teaspoons salt
5 large eggs, room temperature
2 cups (452 g) sour cream or Greek yogurt, room temperature
1/2 cup plus 2 tablespoons (142 g) unsalted butter, softened
Optional Garnish: chocolate sprinkles, curls, or chips
Instructions
Preheat oven to 350°F (180°C). Grease and line four 9-inch round cake pans with parchment.
Sift together flour, sugar, cocoa powder, baking soda, baking powder, and salt. Add eggs, sour cream, water, oil, and vanilla. Mix until smooth.
Divide batter evenly among pans. Bake about 25 minutes until a toothpick comes out clean. Cool 15 minutes, then transfer to racks to cool completely. Chill for easier slicing.
Prepare simple syrup by heating sugar and water until dissolved. Cool completely.
For pastry cream, heat milk, cream, half the sugar, and salt until simmering. Whisk yolks with remaining sugar and cornstarch. Temper with hot milk, return to heat, and cook until thick. Remove from heat and stir in butter, chocolate, and vanilla. Strain, cover surface, and chill.
For frosting, heat cream, sugar, and salt until simmering. Pour over chopped chocolate and whisk smooth. Add butter and whisk until glossy. Chill until spreadable.
Level cakes and slice each into three layers, creating 12 layers total.
Line a cake ring with acetate. Place first layer inside, brush with syrup, and spread just over 1/2 cup pastry cream. Add next layer, brush with syrup, and spread frosting. Continue alternating fillings until 6 layers are stacked. Freeze until firm.
Repeat with remaining layers to form a second 6-layer stack. Freeze until very firm.
Remove from molds and stack one cake atop the other. Smooth sides and garnish as desired. Bring to room temperature before serving.
Notes
Chilling cake layers before slicing ensures clean, even layers.
The cake can be assembled and frozen ahead of time.
Use semisweet chocolate for a slightly lighter flavor.
Add espresso powder to enhance chocolate depth.
Allow cake to sit at room temperature before serving for best texture.
