Mocha Layer Cake with Chocolate-Rum Cream Filling

Yield: 1 (8-inch) three-layer cake | Serves: 12-14
Prep Time: 45 minutes | Cook Time: 30 minutes | Chill Time: 2 hours | Total Time: 3 hours 15 minutes
Intensity Level: Medium (Involves multiple components and careful assembly, but steps are clearly defined.)

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Ingredients

For the Mocha Cake Layers:

• 2 ¼ cups (285g) all-purpose flour, spooned and leveled

• 2 ½ teaspoons baking powder

• ½ teaspoon salt

• ¾ cup (75g) natural unsweetened cocoa powder (not Dutch-process)

• 1 tablespoon instant espresso powder

• ¾ cup (170g) unsalted butter, softened to room temperature

• 1 ¾ cups (350g) granulated sugar

• 3 large eggs, room temperature

• 2 teaspoons pure vanilla extract

• 1 ½ cups (360ml) whole milk, room temperature

For the Chocolate-Rum Syrup:

• ½ cup (120ml) water

• ¼ cup (50g) granulated sugar

• 2 tablespoons dark rum

• 1 tablespoon unsweetened cocoa powder

For the Chocolate-Rum Cream Filling:

• 2 cups (480ml) heavy whipping cream, cold

• ½ cup (60g) confectioners’ sugar, sifted

• ⅓ cup (35g) unsweetened cocoa powder, sifted

• 2 tablespoons dark rum

• 1 teaspoon pure vanilla extract

• 1 ½ cups (255g) semi-sweet chocolate chips, finely chopped, or high-quality dark chocolate bar, finely chopped

For the Mocha Whipped Cream Frosting:

• 2 ½ cups (600ml) heavy whipping cream, cold

• ¾ cup (90g) confectioners’ sugar, sifted

• ¼ cup (25g) unsweetened cocoa powder, sifted

• 1 tablespoon instant espresso powder dissolved in 1 teaspoon hot water, cooled

• 1 teaspoon pure vanilla extract

For Garnish (Optional):

• Chocolate shavings or curls

• Light dusting of cocoa powder or espresso powder

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Equipment

• Three 8-inch round cake pans

• Parchment paper

• Stand mixer or hand mixer

• Mixing bowls

• Sieve or sifter

• Cooling racks

• Small saucepan

• Pastry brush

• Serrated knife or cake leveler

• Offset spatula

• Piping bag and star tip (optional, for decoration)

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Instructions

1. Bake the Cake Layers

1. Prep: Preheat your oven to 350°F (175°C). Grease the bottoms and sides of three 8-inch round cake pans. Line the bottoms with parchment paper circles and lightly grease the paper.

2. Mix Dry Ingredients: In a medium bowl, whisk together the flour, baking powder, and salt. In a separate small bowl, combine the cocoa powder and instant espresso powder.

3. Cream Butter & Sugar: In the bowl of a stand mixer fitted with the paddle attachment (or using a hand mixer), beat the softened butter and granulated sugar on medium-high speed for 3-4 minutes, until light, fluffy, and pale in color.

4. Add Eggs & Vanilla: Add the eggs one at a time, beating well after each addition and scraping down the bowl as needed. Beat in the vanilla extract.

5. Combine Wet & Dry: With the mixer on low speed, add the dry flour mixture in three additions, alternating with the milk in two additions, beginning and ending with the flour mixture. Mix just until each addition is incorporated. Do not overmix.

6. Add Cocoa/Espresso: In a final step, add the cocoa-espresso powder mixture and mix on low until just combined and no dry streaks remain. The batter will be thick.

7. Bake: Divide the batter evenly among the prepared pans (a kitchen scale ensures perfect layers). Smooth the tops. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.

8. Cool: Let the cakes cool in their pans on a wire rack for 15 minutes. Then, carefully run a knife around the edges and invert them onto the racks to cool completely. Peel off the parchment paper.

2. Make the Chocolate-Rum Syrup

While the cakes cool, combine the water and sugar in a small saucepan. Bring to a simmer over medium heat, stirring until sugar dissolves. Remove from heat and whisk in the cocoa powder and rum until smooth. Let cool to room temperature.

3. Prepare the Chocolate-Rum Cream Filling

1. Place the finely chopped chocolate in a heatproof bowl. Heat ½ cup of the heavy cream in a small saucepan until it just begins to simmer. Pour the hot cream over the chocolate, let it sit for one minute, then stir gently until completely smooth and glossy. This is your chocolate ganache. Stir in the rum and vanilla. Let it cool to room temperature (it should be thick but still pourable).

2. In a clean mixer bowl, whip the remaining 1 ½ cups of cold heavy cream with the confectioners’ sugar and cocoa powder on medium-high speed until soft peaks form.

3. Gently fold the cooled chocolate ganache into the whipped cream until fully combined and smooth. Be careful not to deflate the mixture. Cover and refrigerate for at least 30 minutes to firm up slightly.

4. Assemble the Cake

1. Level: Using a serrated knife or cake leveler, carefully slice the domed tops off the cooled cake layers to create flat, even surfaces.

2. Soak: Place one cake layer on your serving plate or cake stand. Using a pastry brush, generously brush the surface with about one-third of the chocolate-rum syrup.

3. Fill: Spread half of the chilled Chocolate-Rum Cream Filling evenly over the soaked layer, leaving a small border around the edge to prevent squeezing out.

4. Stack: Place the second cake layer on top. Brush with syrup, then spread with the remaining filling. Top with the final cake layer and brush with the remaining syrup. Press down gently.

5. Frost with Mocha Whipped Cream

1. Chill: For a stable crumb coat, place the assembled cake in the refrigerator for 20-30 minutes.

2. Make Frosting: Dissolve the espresso powder in hot water and let cool. In a chilled mixer bowl, combine all frosting ingredients: cold heavy cream, confectioners’ sugar, sifted cocoa powder, cooled espresso mixture, and vanilla. Whip on medium-high speed until stiff peaks form.

3. Frost: Apply a thin “crumb coat” of frosting all over the cake to seal in crumbs. Chill for 15 minutes. Use the remaining frosting to create a beautiful final coat, smoothing the sides and top with an offset spatula.

4. Decorate (Optional): Pipe decorative borders or swirls on top with any remaining frosting. Garnish with chocolate shavings and a light dusting of cocoa or espresso powder.

6. Chill and Serve

For clean slices and the best texture, cover the cake loosely and refrigerate for at least 1-2 hours before serving. This allows the flavors to meld and the filling to set perfectly. Use a sharp knife dipped in hot water and dried between slices for pristine cuts.

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Nutritional Information (Per serving, approximately 1 slice)

• Calories: ~680 kcal

• Total Fat: 45g

  • Saturated Fat: 28g

• Cholesterol: 155mg

• Sodium: 220mg

• Total Carbohydrates: 65g

  • Dietary Fiber: 5g

  • Sugars: 42g

• Protein: 9g

Note: Nutritional information is an estimate calculated using standard ingredient databases. Values may vary based on specific brands and measurements used.

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Chef’s Notes & Tips for Success

• Room Temperature is Key: Using room temperature eggs, milk, and butter ensures the cake batter emulsifies properly for a fine, even crumb.

• Espresso Power: Instant espresso powder intensifies the chocolate flavor without making the cake taste strongly of coffee. For a non-alcoholic version, omit the rum from the syrup and filling, replacing it with 1 teaspoon of rum extract or additional milk/cream.

• Filling Stability: Ensure your ganache is cooled to room temperature before folding it into the whipped cream. If it’s too warm, it will melt the cream; if too cold, it will be difficult to incorporate smoothly.

• Make Ahead: Cake layers can be baked, cooled, wrapped tightly in plastic wrap, and frozen for up to 1 month. Thaw in the refrigerator before assembling. The unfrosted, assembled cake (with filling) can be refrigerated overnight before final frosting.

• Storage: Store leftovers covered in the refrigerator for up to 4 days. The whipped cream frosting will hold its shape beautifully.