Matilda's Chocolate Cake

A towering three-layer chocolate cake, deeply moist from buttermilk, sour cream, and coffee, and completely covered in a thick, glossy chocolate fudge frosting swooped into big, decadent swirls.

Prep Time 45

Cook Time 35

Cooling and Frosting 2

Total Time 3 20

Equipment

Ingredients

Chocolate Fudge Frosting

▢ 425 g semisweet chocolate finely chopped (15 ounces)
▢ 280 g unsalted butter 1¼ cups
▢ 450 g heavy cream 1⅞ cups
▢ 75 g Dutch-process cocoa powder ¾ cup
▢ 185 g granulated sugar ¾ cup + 3 tablespoons
▢ 2 teaspoons vanilla extract
▢ ¾ teaspoon fine salt

Instructions

Make the Chocolate Cake

Preheat the oven to 350°F (175°C). Grease three 8-inch round cake pans and line the bottoms with parchment paper.
In a large mixing bowl, whisk together the flour, cocoa powder, granulated sugar, baking soda, baking powder, and salt.
300 g all-purpose flour, 100 g Dutch-process cocoa powder, 500 g granulated sugar, 2 teaspoons baking soda, 1¼ teaspoons baking powder, 1 teaspoon fine salt
In a separate bowl, whisk together the eggs, sour cream, buttermilk, oil, and vanilla until smooth.
3 large eggs, 240 g full-fat sour cream, 180 g buttermilk, 180 g neutral oil, 1 tablespoon vanilla extract
Pour the wet ingredients into the dry ingredients and whisk until mostly combined.
Slowly pour in the hot coffee while whisking. Continue mixing just until the batter is smooth and evenly combined. The batter will be fairly thin.
240 g hot brewed coffee
Divide the batter evenly between the three prepared cake pans.
Bake for 30-35 minutes, or until the centers spring back lightly when touched and a toothpick inserted into the center comes out with a few moist crumbs. The internal temp should be around 200 F.
Allow the cakes to cool in the pans for 10–15 minutes. Turn them out onto wire racks and cool completely before frosting.

Make the Chocolate Fudge Frosting

Place the finely chopped semisweet chocolate in a large heatproof bowl.
425 g semisweet chocolate
Add the butter, heavy cream, cocoa powder, and granulated sugar to a medium saucepan.
280 g unsalted butter, 450 g heavy cream, 75 g Dutch-process cocoa powder, 185 g granulated sugar
Heat over medium-low heat, whisking frequently, until the butter has completely melted, the cocoa is incorporated, and the sugar has dissolved.
Continue heating until the mixture reaches approximately 175–185°F (79–85°C). It should be hot and steaming but not vigorously boiling.
Immediately pour the hot cream mixture over the chopped chocolate. Let stand undisturbed for 2–3 minutes.
Starting in the center of the bowl, whisk slowly until the chocolate has completely melted and the frosting is smooth and glossy.
Whisk in the vanilla and salt.
2 teaspoons vanilla extract, ¾ teaspoon fine salt
Allow the frosting to cool at room temperature, stirring occasionally, until thick and spreadable. This can take approximately 1–2 hours depending on the temperature of your kitchen. The frosting will thicken considerably as it cools.

Assemble the Cake

Place one completely cooled cake layer on a cake board or serving plate.
Spread a generous layer of chocolate fudge frosting evenly over the top.
Place the second cake layer on top and spread with another generous layer of frosting.
Add the final cake layer.
Cover the top and sides of the cake generously with the remaining chocolate fudge frosting.
Use an offset spatula or the back of a spoon to create large swoops and swirls in the frosting for a thick, decadent, Matilda-style finish.
Allow the cake to sit at room temperature for 20–30 minutes before serving if it has been refrigerated.

Notes

Chocolate: For a rich but balanced frosting, use good-quality semisweet chocolate around 55–65% cacao. Please note that this is a very rich cake by design!

Cocoa powder: Dutch-process cocoa gives the cake its characteristic deep color and rich chocolate flavor.

Coffee: The hot coffee intensifies the chocolate flavor without making the finished cake taste strongly of coffee. I usually just heat up some cold brew I already have in the fridge.

Do not overbake: For the moistest crumb, remove the cakes when a toothpick comes out with a few moist crumbs rather than completely clean. This takes 30-35 mins for me. The internal temp should be around 200 F.

Frosting consistency: The frosting will initially be quite fluid. Give it plenty of time to cool before deciding it's too thin — it becomes thick, glossy, and spreadable as it approaches room temperature.

Make ahead: The cake layers can be baked one day in advance. Once completely cool, wrap them tightly until ready to assemble.

Storage: Store the assembled cake covered in the refrigerator for up to 4 days. For the best texture and flavor, bring it to room temperature before serving.

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