Professional Baker Teaches You How To Make Chocolate Mousse Cake

Ingredients

• 2 oz Unsweetened Chocolate (high‑quality, chopped)
• 1/4 cup Unsalted Butter (softened, cut into cubes)
• 1/2 cup Boiling Water (freshly boiled)
• 1 Large Egg (room temperature)
• 1/2 cup Granulated Sugar (for cake batter)
• 1 tsp Vanilla Extract (pure extract)
• 1 1/4 cup All-Purpose Flour (sifted)
• 1 tsp Baking Powder
• 3/4 tsp Baking Soda
• 1 pinch Salt
• 1/2 cup Strong Coffee (hot, brewed strong)
• 1.5 cup Heavy Whipping Cream (for chocolate ganache)
• 12 oz Bittersweet Chocolate (60‑70% cacao, chopped)
• 1/2 cup Granulated Sugar (for sugar syrup)
• 1/3 cup Water (for sugar syrup)
• 3 Egg Yolks (separated from large eggs)
• 1.5 cup Heavy Whipping Cream (whipped to soft peaks for mousse folding)
• 2 oz Chocolate for Glaze (finely chopped)
• 1 tbsp Unsalted Butter (for glaze) (softened)

Instructions

1. Melt Chocolate and Butter

   Measure 1/2 cup boiling water and pour it over 2 oz chopped unsweetened chocolate and 1/4 cup unsalted butter in a heat‑proof bowl. Stir until just combined; the mixture will look grainy. Let it sit for a few minutes to soften.

   Time: PT5M

2. Whisk Egg, Sugar, and Vanilla

   In a separate mixing bowl, crack 1 large egg, add 1/2 cup granulated sugar and 1 tsp vanilla extract. Whisk with an electric mixer on medium speed until the mixture becomes pale, thick, and roughly doubled in volume.

   Time: PT5M

3. Combine Wet Ingredients

   Add the chocolate‑butter mixture to the egg‑sugar foam. Mix on low speed until just incorporated; the batter will be very wet.

   Time: PT2M

4. Sift and Add Dry Ingredients

   Sift 1 ¼ cup all‑purpose flour, 1 tsp baking powder, 3/4 tsp baking soda, and a pinch of salt directly over the batter. Fold gently with a spatula until no streaks remain.

   Time: PT5M

5. Add Hot Coffee

   Stir in 1/2 cup hot, strong coffee. The coffee intensifies the chocolate flavor without adding extra liquid.

   Time: PT1M

6. Bake the Chocolate Sponge

   Divide the batter between two greased 8‑inch cake pans. Bake in a pre‑heated 325°F oven for about 25 minutes, or until a toothpick inserted in the center springs back.

   Time: PT25M

   Temperature: 325°F

7. Prepare Chocolate Ganache

   In a saucepan, bring 1.5 cup heavy whipping cream to a simmer. Remove from heat and pour over 12 oz chopped bittersweet chocolate. Let sit 1 minute, then stir gently until smooth.

   Time: PT5M

8. Cook Sugar Syrup

   Combine 1/2 cup granulated sugar and 1/3 cup water in a small saucepan. Cook over medium heat, stirring until dissolved, then attach a candy thermometer and continue cooking until the syrup reaches 250°F.

   Time: PT7M

9. Whisk Egg Yolks

   Separate 3 egg yolks from their whites. Lightly whisk the yolks in a clean bowl to loosen them.

   Time: PT2M

10. Combine Yolks with Hot Syrup

    With the mixer on high, slowly drizzle the 250°F sugar syrup into the whisked yolks, pouring down the side of the bowl. Continue mixing until the mixture cools to about body temperature and becomes thick and glossy.

    Time: PT5M

11. Incorporate Ganache

    Pour the cooled chocolate ganache into the yolk‑syrup mixture and stir until fully blended. Allow the mixture to cool completely to room temperature before adding whipped cream.

    Time: PT30M

12. Whip Cream for Mousse

    Whip 1.5 cup heavy whipping cream to soft peaks using the electric mixer.

    Time: PT5M

13. Fold Whipped Cream into Mousse Base

    Gently fold the whipped cream into the cooled chocolate‑yolk mixture until a uniform, airy mousse forms.

    Time: PT5M

14. Prepare Cake Layers

    Once the baked cakes are completely cooled, use a cake wheel (or sharp knife) to slice each cake horizontally, creating thin sponge layers.

    Time: PT5M

15. Assemble the Cake

    Line a 9‑inch springform pan with parchment. Spread half of the mousse in the bottom, place one sponge layer, then spread the remaining mousse, and finally top with the second sponge layer. Smooth the top.

    Time: PT5M

16. Freeze to Set

    Cover the assembled cake and place it in the freezer for 4–6 hours, or until the mousse is firm.

    Time: PT4H30M

17. Prepare Chocolate Glaze

    Melt 2 oz chocolate with 1 tbsp unsalted butter over a double boiler or in short bursts in the microwave, stirring until smooth.

    Time: PT5M

18. Glaze the Cake

    Remove the cake from the freezer, unmold using a hair dryer to warm the sides of the springform pan just enough for release. Pour the chocolate glaze over the top, allowing it to drip down the sides.

    Time: PT5M

19. Final Chill and Serve

    Re‑freeze the glazed cake for 15 minutes to set the glaze, then slice with a hot knife for clean cuts. Serve chilled.

    Time: PT15M

Nutrition Facts

Calories

450

Protein

5 g

Carbohydrates

45 g

Fat

30 g

Fiber

3 g

Ingredient Substitutions

• Instead of Unsweetened Chocolate: Dark chocolate (70% cacao)
• Instead of Unsalted Butter: Salted butter (reduce added salt)
• Instead of Large Egg: Egg replacer (not recommended for mousse)
• Instead of Granulated Sugar: Superfine sugar
• Instead of Vanilla Extract: Vanilla bean (scrape)
• Instead of All-Purpose Flour: Cake flour (for lighter texture)
• Instead of Baking Powder: Cream of tartar + baking soda
• Instead of Baking Soda: Baking powder (increase amount)
• Instead of Strong Coffee: Espresso
• Instead of Heavy Whipping Cream: Half‑and‑half (less rich)
• Instead of Bittersweet Chocolate: Dark chocolate (70% cacao)
• Instead of Granulated Sugar: Superfine sugar
• Instead of Egg Yolks: Pasteurized egg yolks
• Instead of Heavy Whipping Cream: Chilled coconut cream (non‑dairy)
• Instead of Chocolate for Glaze: Additional bittersweet chocolate
• Instead of Unsalted Butter (for glaze): Margarine

Equipment Needed

• Mixing Bowl
• Saucepan
• Candy Thermometer
• Whisk
• Electric Mixer
• Fine Mesh Sieve
• 8‑Inch Cake Pan
• 9‑Inch Springform Pan
• Cake Wheel (optional)
• Spatula
• Oven
• Freezer
• Hair Dryer (optional)

Critical Steps — Do Not Skip

• Melting chocolate and butter without seizing
• Cooking sugar syrup to the exact 250°F temperature
• Cooling the chocolate‑yolk mixture completely before folding in whipped cream
• Freezing the assembled cake for 4–6 hours to set the mousse
• Unmolding the cake using a hair dryer to avoid glaze cracking

Chef Tips from the Video

• Use high‑quality bittersweet chocolate for the deepest flavor.
• Add a teaspoon of espresso powder to the coffee for an extra coffee‑chocolate boost.
• When folding the mousse, use a large rubber spatula and turn the bowl slowly to preserve air.

Troubleshooting

Storage

Refrigerator: Store leftovers tightly covered for up to 3 days.

Freezer: Freeze individual slices wrapped in plastic and foil for up to 1 month.

Room temperature: Do not store at room temperature; the mousse will soften.

Make-Ahead Tips

• Bake the sponge layers a day ahead and store them wrapped in plastic.
• Prepare the chocolate mousse up to the folding stage and keep it refrigerated; add the final whipped cream just before assembly.
• The glaze can be made up to 2 hours ahead; keep it warm and fluid.

Frequently Asked Questions