Chocolate cake with blueberry mousse

Ingredients

Chocolate sponge biscuit

3 large eggs
100 grams (1/2 cup) sugar
80 grams (2/3 cup) flour
15 grams (1 tablespoon) cornstarch
2 teaspoons baking powder
30 grams (1/4 cup) cocoa powder
75 grams (1/3 cup) vegetable oil
60 milliliters (1/4 cup) hot milk

Blueberry mousse

10 grams (1 tablespoon) gelatin (180-200 bloom)
180 grams (3/4 cup) blueberry puree
310 grams (11 ounces) white chocolate
350 grams (1 1/2 cups) whipping cream

Equipment

Mixing Bowls
You'll need separate bowls for mixing the egg yolks, egg whites, and the dry ingredients. Stainless steel or glass bowls are best for whipping egg whites.
Hand Mixer or Stand Mixer
Essential for whipping egg whites to firm peaks and achieving smooth, lump-free batter and mousse. Make sure the beaters are clean and dry.
Sifter
A sifter ensures your dry ingredients are free of lumps, which is crucial for a smooth batter. Don't skip this step!
14cm (5.51 inch) Cake Pans
You'll need two of these to bake your sponge cakes. Make sure to line them with parchment paper for easy release.
Spatula
Perfect for folding the egg whites into the batter. Use a rubber spatula to gently combine ingredients without deflating the mixture.
Freezer
Crucial for setting the mousse layers between each addition. Ensure you have space to accommodate your cake.

Instructions

Step 1

Divide the eggs into whites and yolks. Whip the yolks with half of the sugar until pale and creamy. This can take about 3-5 minutes.

Step 2

Add the sifted cocoa powder to the yolk mixture, and whisk until well combined.

Step 3

Slowly pour in the hot milk, whisking immediately until smooth. Make sure the milk is very hot but not boiling.

Step 4

Combine the dry ingredients: flour, cornstarch, and baking powder. Gently add them to the yolk mixture, and fold in the vegetable oil. Whisk with a mixer until smooth.

Step 5

In another bowl, whip the egg whites until foamy using a mixer. Gradually add the remaining sugar, and continue to whip until firm peaks form.

Step 6

Fold a small amount of the whipped egg whites into the chocolate mixture to lighten it. Then gently fold in the remaining whites until well combined.

Step 7

Bake the sponge biscuit in two 14 cm (5.5 inch) molds at 320°F (160°C) for 40 minutes. Use a toothpick to test for doneness; it should come out clean.

Step 8

Once cooled, cut each sponge biscuit into two layers, and remove the top crust.

Step 9

Soak the gelatin in cold water until softened. This typically takes about 5 minutes.

Step 10

Heat the blueberry puree until it's warm, then pour it over the white chocolate. Mix until smooth.

Step 11

Dissolve the soaked gelatin in the warm chocolate mixture, stirring until fully incorporated. Ensure there are no lumps of gelatin.

Step 12

In another bowl, whip the cream until soft peaks form. Be careful not to over-whip the cream.

Step 13

Combine the whipped cream and the chocolate mixture, ensuring the chocolate mixture is no more than 95°F (35°C). If it's too warm, let it cool slightly before combining.

Step 14

Pre-divide the mousse into 3 equal parts to make assembling easier. Using a measuring cup can help ensure even layers.

Step 15

Assemble the cake by pouring one part of the mousse over a sponge biscuit layer. Repeat for each layer. Tip: Place the cake in the freezer for 5-10 minutes after each mousse addition for a more even and beautiful finish. Span class='tip'>This helps keep the layers from mixing and ensures a clean cut.

Servings

💡 Serving Suggestions:

🎉 **Make it a centerpiece:** This cake is so stunning it deserves the spotlight. Place it on a pretty cake stand and let it be the star of your dessert table. Top with a handful of fresh blueberries and a dusting of powdered sugar for an extra elegant touch.

🌟 **Pair it with a drink:** Serve with a chilled glass of sparkling wine for adults or a simple vanilla-flavored milkshake for kids to balance out the rich chocolate and creamy mousse.

🍴 **Slice smart:** For the perfect slice, use a sharp knife heated with hot water and wiped dry. This will give you clean cuts and showcase the beautiful layers.

🎁 **Gift it:** This cake makes an exquisite gift. Place it in a pretty cake box with a ribbon, and you've got a delicious homemade present that anyone would love to receive.

Variations

🌱 **Gluten-Free Variation:** Replace the flour with an equal amount of gluten-free all-purpose flour blend. Ensure the baking powder you use is also gluten-free. Your sponge will turn out just as fluffy and delicious!

💚 **Vegan Variation:** Substitute the eggs with chia or flax seeds (1 tablespoon flax/chia seeds mixed with 3 tablespoons water per egg). Use coconut cream instead of whipping cream and agar-agar in place of gelatin. Opt for dairy-free white chocolate to complete the transition.

Faq

Why is my sponge cake dense and not fluffy?
Ensure you're beating the egg whites to firm peaks and folding them gently into the batter to keep as much air as possible.
Can I make the mousse without gelatin?
Yes, you can use agar-agar as a vegetarian substitute for gelatin. Follow packet instructions for correct proportions.
How should I store the cake if I make it in advance?
Store the assembled cake in an airtight container in the fridge for up to three days. You can also freeze it for longer storage; just let it thaw in the fridge for a few hours before serving.
Why did my mousse not set properly?
Make sure to properly dissolve the gelatin in the heated puree and then cool the mixture to the right temperature before combining with whipped cream.
How can I enhance the blueberry flavor?
You can add a tablespoon of blueberry extract or a few drops of blueberry essence to the mousse mixture for a more intense flavor.
Can I make the cake layers thicker and cut them afterwards?
Yes, you can bake thicker sponge cakes in a taller mold and carefully slice them into thinner layers once they cool completely. Adjust baking time to ensure the cake is fully cooked.