Chocolate Cake with Passion Fruit Mousse
Forget everything you think you know about chocolate cake. We are going beyond the usual.
This recipe pairs deep, rich chocolate with a bright, tangy passion fruit mousse. The contrast is the entire point.
It’s an elegant dessert that looks complex but is built from simple, straightforward steps. Follow them precisely for a perfect outcome.
Let’s begin.
What You’ll Need
Accurate measurements are critical. Use what is listed.
For the Chocolate Cake:
- 1 3/4 cups all-purpose flour
- 2 cups granulated sugar
- 3/4 cup unsweetened cocoa powder
- 2 teaspoons baking soda
- 1 teaspoon baking powder
- 1 teaspoon salt
- 1 cup buttermilk, room temperature
- 1/2 cup vegetable oil
- 2 large eggs, room temperature
- 1 teaspoon vanilla extract
- 1 cup freshly brewed hot coffee
For the Passion Fruit Mousse:
- 1 cup passion fruit puree, seedless
- 1/2 cup granulated sugar
- 1 tablespoon (1 packet) unflavored gelatin
- 1/4 cup cold water
- 1 1/2 cups heavy whipping cream, chilled
For the Chocolate Ganache:
- 8 ounces dark chocolate (60-70% cacao), finely chopped
- 1 cup heavy whipping cream
Tools Required
- Two 9-inch round cake pans
- Parchment paper
- Mixing bowls (large, medium, small)
- Whisk
- Spatula
- Electric mixer (stand or hand-held)
- Saucepan
- Offset spatula
- Wire cooling rack
Pro Tips
These small details make a significant difference. Do not skip them.
- Room Temperature Ingredients: Your wet ingredients for the cake (buttermilk, eggs) must be at room temperature. This allows them to blend into a smooth batter, creating a lighter, more even cake crumb. Cold ingredients can cause the batter to curdle.
- Don’t Scorch the Puree: When heating the passion fruit puree for the mousse, use low, gentle heat. You only want to warm it enough to dissolve the sugar and gelatin. Boiling it can alter the fresh, tangy flavor you want.
- The Ganache “Break”: When you pour the hot cream over the chocolate, let it sit untouched for 5 minutes. This allows the heat to gently melt the chocolate. Stirring too soon will cool it down prematurely, resulting in a grainy ganache. Patience here yields a silky-smooth finish.
- Chill for a Clean Slice: The final cake needs at least 4 hours in the refrigerator, but 6-8 hours is better. This gives the mousse time to fully set and firm up. A well-chilled cake will give you beautiful, clean layers when you slice into it.
The Step-by-Step Instructions
Follow this sequence exactly. Each stage builds on the last.
Part 1: The Chocolate Cake
Step 1: Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans. Line the bottoms with parchment paper.
Step 2: In a large bowl, whisk together the flour, sugar, cocoa powder, baking soda, baking powder, and salt. Break up any lumps.
Step 3: In a separate medium bowl, combine the buttermilk, oil, eggs, and vanilla extract. Whisk until just combined.
Step 4: Pour the wet ingredients into the dry ingredients. Mix on low speed with an electric mixer until just combined. Do not overmix.
Step 5: Carefully pour the hot coffee into the batter. Mix on low speed until the batter is smooth. It will be very thin; this is normal.
Step 6: Divide the batter evenly between the two prepared pans. Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.
Step 7: Let the cakes cool in the pans on a wire rack for 15 minutes. Then, invert them onto the rack, remove the parchment paper, and let them cool completely.
Part 2: The Passion Fruit Mousse
Step 1: In a small bowl, sprinkle the gelatin over the 1/4 cup of cold water. Let it sit for 5-10 minutes to bloom.
Step 2: In a saucepan over low heat, warm the passion fruit puree and sugar. Stir until the sugar is completely dissolved. Do not let it boil.
Step 3: Remove the puree from the heat. Add the bloomed gelatin and stir until it has completely dissolved into the warm puree. Set aside and let it cool to room temperature.
Step 4: In a separate chilled bowl, use an electric mixer to whip the 1 1/2 cups of heavy cream until stiff peaks form.
Step 5: Gently fold the cooled passion fruit mixture into the whipped cream in three additions. Be careful not to deflate the cream. The mousse should be light and airy.
Part 3: Assembly
Step 1: Once the cake layers are completely cool, level them if needed using a serrated knife. Place one cake layer on your serving plate or a cake stand.
Step 2: If you have a 9-inch cake ring or the collar of a springform pan, place it around the cake layer. This helps create a neat, stable layer of mousse.
Step 3: Pour all of the passion fruit mousse onto the cake layer. Use a spatula to spread it evenly to the edges.
Step 4: Gently place the second cake layer on top of the mousse. Lightly press it down.
Step 5: Transfer the assembled cake to the refrigerator. Chill for at least 4 hours, or until the mousse is fully set and firm to the touch.
Part 4: The Chocolate Ganache
Step 1: Place the finely chopped dark chocolate in a heatproof bowl.
Step 2: Heat the 1 cup of heavy cream in a saucepan over medium heat until it just begins to simmer around the edges. Do not let it boil over.
Step 3: Pour the hot cream directly over the chopped chocolate. Let it stand for 5 minutes without stirring.
Step 4: After 5 minutes, gently whisk the mixture, starting from the center and working your way out, until the ganache is smooth and glossy.
Step 5: Let the ganache cool for about 10-15 minutes. It should be thick but still pourable.
Step 6: Remove the chilled cake from the refrigerator. Carefully remove the cake ring if you used one. Pour the ganache over the top of the cake, using an offset spatula to gently guide it over the edges for a drip effect.
Step 7: Return the cake to the refrigerator for another 30 minutes to allow the ganache to set before serving.
Time and Nutritional Overview
This table provides estimates. Actual times and values may vary.
| Time Element | Duration |
|---|---|
| Prep Time | 45 minutes |
| Cook Time | 35 minutes |
| Chill Time | 4.5+ hours |
| Total Time | ~6 hours |
| Nutrient (per slice, approx.) | Amount |
|---|---|
| Calories | 550 kcal |
| Carbohydrates | 65g |
| Protein | 7g |
| Fat | 30g |
Substitutions and Variations
Modifications can be made, but they will alter the final result.
| Dietary Need | Suggested Swap |
|---|---|
| Gluten-Free | Use a 1:1 gluten-free all-purpose flour blend containing xanthan gum. |
| Dairy-Free / Vegan | Use plant-based buttermilk (soy/almond milk + vinegar), coconut oil, full-fat coconut cream for mousse/ganache, and a flax egg replacer. Use agar-agar for gelatin. |
| Different Fruit | Mango, raspberry, or lime puree can replace passion fruit puree in the mousse. |
Leftovers and Storage
Store any leftover cake in an airtight container in the refrigerator. It will keep for up to 4 days.
The mousse will keep its texture well in the cold. The cake may become slightly denser upon chilling but will remain moist.
Freezing is possible. Wrap individual slices tightly in plastic wrap, then foil. Freeze for up to 1 month. Thaw in the refrigerator overnight before eating.
Frequently Asked Questions
Q1. My mousse is runny and didn’t set. What went wrong?
Ans: This is usually a gelatin issue. Ensure your gelatin bloomed correctly in cold water and fully dissolved in the warm puree. Also, the passion fruit mixture must be cooled to room temperature before folding it into the whipped cream. A warm mixture will melt the cream.
Q2. Can I use bottled passion fruit juice instead of puree?
Ans: It is not recommended. Passion fruit puree is thicker and has a more concentrated flavor. Juice is thinner and often contains extra sugar or water, which will affect the mousse’s consistency and taste. Seek out frozen or canned puree.
Q3. Why is my chocolate cake dry?
Ans: The two most common reasons are overbaking and mis-measuring flour. Bake only until a toothpick comes out clean; any longer will dry it out. When measuring flour, spoon it into your measuring cup and level it off. Scooping directly from the bag compacts the flour, adding too much to the recipe.
Q4. Can I make this in a different sized pan?
Ans: You can, but you must adjust the baking time. For an 8-inch pan, the layers will be thicker and require longer baking. For a 13×9 inch sheet pan, the cake will be thinner and bake much faster. Watch it closely.
Wrapping Up
You now have the complete blueprint for this cake. The process is precise, but the reward is a truly impressive dessert.
The combination of rich chocolate and vibrant passion fruit is a proven success. Create it for yourself.
When you finish, leave a comment below. Describe your result and share any questions that came up during your process.
