Chocolate Mousse Cake

If you’re even slightly obsessed with chocolate, this cake is going to ruin every other dessert for you — in the best way. It’s a triple-layered dream with a soft chocolate cake at the bottom, a cloud of chocolate mousse in the middle, and a glossy ganache on top. Every bite is like a full-on chocolate hug — rich, light, and silky all at once.

This is the kind of dessert that’s perfect for birthdays, dinner parties, or, let’s be honest, an average Tuesday night when you’re just in the mood for something spectacular. I made this last winter when we had guests over, and one slice in, there was total silence around the table — except for the sound of spoons scraping plates.

The Chocolate Cake Base

Before we get to the fancy mousse and ganache, let’s talk about the base — a rich, moist chocolate cake that doesn’t crumble when sliced, yet melts in your mouth.

This one’s my go-to chocolate cake recipe — oil-based (so no waiting for butter to soften), with dark Dutch cocoa and a splash of hot coffee. The batter comes together in one bowl and stays tender thanks to a few things:

• Cornstarch – Just a spoonful makes the cake texture softer and finer. Think bakery-style.

• Dutch Cocoa – This is the good stuff — darker, smoother, and gives the cake that rich color and depth of flavor.

• Sour Cream – Adds body and a bit of tang, which balances all the sweetness.

• Hot Coffee – Don’t skip this. It’s not about adding coffee flavor; it helps the cocoa “bloom” and intensifies the chocolate like nothing else.

Extra tip: Once the cake cools, I slice off the dome to make a flat base. Then I spoon a quick coffee-cocoa soak over the top. It’s optional, but honestly, it makes a massive difference — the cake turns extra moist and flavorful, like it’s been sitting overnight in the best way possible.

Making That Dreamy Chocolate Mousse

Okay, fair warning — you’ll use more bowls than usual here. But trust me, it’s worth every dish.

I love this mousse because it hits the sweet spot: rich but not heavy, chocolaty but not overwhelming.

Here’s the breakdown:

Step 1 – Melting Chocolate

I use equal parts 70% dark and milk chocolate. That way, you get richness without bitterness, and it doesn’t end up tasting like a bar of baking chocolate. Use good-quality chocolate if you can — it really makes a difference.

After melting it slowly over simmering water, I let it cool a bit before whisking in egg yolks. Yes, raw eggs. No, you won’t taste them. They give the mousse that signature silky finish.

Step 2 – Gelatin and Cream

This part’s what helps the mousse hold its shape. You sprinkle unflavored gelatin over a little water and let it bloom (which is just a fancy way of saying it turns jelly-like). Then you stir that into warm cream — not boiling — just until it steams.

That warm cream gets whisked into the chocolate, bringing everything together smoothly.

Step 3 – The Airy Part

Here’s where the mousse gets its “mousse-ness.”
You whip cream into stiff peaks. Separately, beat egg whites with sugar and cream of tartar into a glossy meringue.

Both go into the chocolate mixture, one after the other, folded in slowly with a spatula. This isn’t a time to rush — gentle folding keeps all the air in, giving you that light, fluffy texture.

Tip: If you overmix or stir too hard, the mousse can get heavy or flat. I usually turn on some music and take my time with this step — it’s kinda relaxing, honestly.

Assembling the Cake

Once the cake is soaked and cooled, and the mousse is ready, it’s time to build this beauty.

I always use a springform pan lined with a tall strip of acetate (you can find it online or at baking stores). It keeps the mousse contained and the sides neat when you unmold the cake.

Just press the acetate between the cake and the pan wall, then pour the mousse over. It should fill right up to the top. The mousse needs at least 4 hours to chill, but overnight is best — that way, it sets evenly, and the flavor deepens.

That Final Ganache Drip

This part is my favorite. Once the cake is chilled and set, I remove the springform ring and gently peel off the acetate — it’s SO satisfying seeing those perfect sides.

Then, pour warm cream over chopped dark chocolate and let it sit for 2-3 minutes. Stir it gently until it’s glossy and smooth.

Pour it right in the center of the cake and gently nudge it to the edges with a spatula — the drips will happen naturally. Chill the whole thing again for about 30 minutes so the ganache firms up just enough to slice cleanly.

How to Serve This Cake

Take it out of the fridge about 30 minutes before serving so the mousse softens a bit. I usually serve it as-is — it doesn’t need anything else. But if you’re feeling fancy, a few chocolate curls or a dusting of cocoa powder on top won’t hurt.

Storing Leftovers

This cake keeps really well in the fridge — I store slices in an airtight container and they last up to a week. The texture holds up beautifully and even improves slightly with time. I’ve also frozen individual slices before — just wrap tightly and thaw in the fridge overnight.

FAQs

Can I make this gluten-free?
Absolutely. Swap in a good-quality 1:1 gluten-free flour blend for the cake layer. Everything else is already gluten-free.

Can I skip the coffee?
You won’t taste it, I promise — it just boosts the chocolate flavor. But if you’re not into it, hot water will work too.

Can I use only dark or only milk chocolate?
You can, but I find the balance of both is what makes the mousse just right — not too bitter, not too sweet.

Do I have to use a springform pan?
Yes — trust me on this. Without a removable bottom, the mousse layer is almost impossible to release without ruining the shape.

What if I don’t have acetate?
You can use parchment paper strips, but acetate gives you those super clean edges. Worth getting if you bake layered desserts now and then.

How long does it take to make?
You’ll want to make it the day before so it has time to chill. Actual hands-on time is about an hour, but there are resting and chilling steps in between.

 

If you try this cake, let me know how it turns out — it’s one of those desserts that makes people stop mid-bite and go, “Wait… did you make this?”

And yes, you did.

Try other Cake recipes:

• One Bowl Chocolate Cake
• Chocolate Bundt Cake
• Orange Chiffon Cake