Fluffy vanilla sponge cake, coffee & chocolate mousse, caramel, and peanuts. The perfect dessert recipe for every occasion!
This cake is exactly what it seems. It’s composed of three layers, each one very different from the other, but also each one complimenting the other in a way that results in a fine dessert. The first layer is a sponge cake, also known as Pan di Spagna. Like I’ve said on my pure chocolate mousse cake post, Pan di Spagna is a perfect base for every mousse to lie on, because it’s very light, soft and fluffy and has the ability to absorb high amounts of syrup without becoming soggy. Some recipes add a little butter, but I prefer not to. I just use whole eggs, sugar and flour (and some cocoa if I want a chocolate version!).
The mousse is made with cream and chocolate. It’s a little like a ganache, with the difference that part of the cream is beaten until soft peaks form, and then combined with the melted chocolate. This technique ensures a very soft, velvety and melt-in-your-mouth mousse. I know some of you aren’t coffee lovers and you’re going to ask if it’s OK to skip the coffee. Yes you can do that if you want to, but I’d suggest adding just a little quantity which will be unnoticeable and will only deepen the flavor. After all, coffee and chocolate have similar flavor profiles. But that’s your decision. For a stronger coffee flavor you can add a teaspoon (or two) of instant espresso powder, along with the espresso shot.
The third layer is salted caramel and peanuts. I used salted peanuts so there was no need to add extra salt, but if you use unsalted peanuts then you should add half a teaspoon fine salt or one teaspoon coarse salt. I had to experiment a little with the caramel, because the cake needs to refrigerated and I didn’t want the caramel hard, but soft, gooey and almost runny. In my chocolate ganache and caramel mars inspired cupcakes I heated the caramel until it reached 226°F (108°C), so I knew that for this recipe the temperature should be a bit lower. So 222°F (106°C) is just right. Unfortunately, you’re going to need a thermometer to achieve the exact consistency. If you don’t mind the caramel being a little runnier or thicker, you can certainly make it according to the instructions and after you add the cream, let it boil for a minute or two, until everything is dissolved and homogenized. I know I’d give it a try with or without a thermometer! 🙂
Some notes – tips:
The secret to a fluffy sponge cake is the thorough beating of the eggs which leads to air being incorporated into the mixture in the form of little air pockets. So make sure you beat them good! When done, they should have at least tripled in volume and have the consistency of shaving foam.
If eggs are warm, they’ll increase in volume much faster, so you can either mix them with the sugar and stir them over a double boiler or you can place them (while still in their shells) in a bowl with hot water (not too hot, you don’t want to boil them!) for a few minutes to warm them up.
When adding the flour you should use a folding motion and not just stir it. This way you’re protecting the little pockets of air from breaking and deflating your mixture. If you’re unsure about the difference between folding and stirring, you can find some videos in YouTube demonstrating this technique.
For this recipe it is best to use a scale for more accurate measurements.
- For the sponge cake:
- 3 large eggs, (150 grams) warm or room temperature
- 1/3 cup (75 grams) sugar
- 1/2 cup (75 grams) all-purpose flour, sifted
- 1 teaspoon vanilla
- A pinch of salt
- For the syrup:
- 1/4 cup water
- 1/4 cup sugar
- 1-2 tablespoons kahlua, optional
- For the mocha mousse:
- 6.2 oz (175 grams) dark chocolate, 55% cocoa
- 2 tablespoons strong espresso
- 1 teaspoon instant espresso powder
- 2 tablespoons brown sugar
- 1/2 cup (100 grams) heavy cream, 35% fat
- 1 1/2 cup (350 grams) heavy cream, 35% fat (you will whip this)
- For the caramel:
- 2/3 cup (150 grams) sugar
- 1 teaspoon glucose or corn syrup
- 3 tablespoons water
- 2/3 cup (150 grams) heavy cream, 35% fat, room temperature
- 1 teaspoon vanilla
- 1/2 cup salted peanuts
Preheat your oven to 350°F (175°C)
Line and grease an 8 or 10 inch spring form pan.
- In the bowl of your electric mixer, beat the eggs, salt, sugar and vanilla until pale and thick like shaving foam.
With a folding motion, add the flour and fold until incorporated.
Transfer into pan and bake for 30-40 minutes or until a toothpick comes out clean with no crumbs at all. Transfer onto a rack and let it cool.
- In the meantime, make the syrup. In a small pot heat sugar with water and let it boil for a minute. Remove from heat and let it cool. Then add the kahlua.
Cut the top crust of the sponge cake and level the surface. Transfer into the spring form pan and brush it with 1/4 cup syrup. Set aside.
- Make the mousse: In a double boiler or in the microwaves melt the chocolate with the cream, the coffee (liquid and powder) and sugar. Let it cool.
Whip the rest of the cream in to soft peaks, add the chocolate mixture and combine well with folding motions.
Pour mixture over the sponge cake and store in the fridge.
- Make the caramel. In a saucepan over medium high heat, melt sugar, glucose and water. Boil until mixture reaches an amber color (the deeper the color the deeper the flavor, but take care not to burn the caramel because it will get bitter).
Remove from heat and carefully add the cream and the vanilla. (the caramel may become solid and form lumps, but it will melt later on)
- Return to heat and boil until mixture is smooth and a thermometer reads 222°F (106°C).
Remove from heat, add the peanuts and let it cool. (you can cool it in an ice bath if you’re in a hurry).
When the caramel has cooled, pour over the mousse and refrigerate for 3-4 hours or overnight.
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