I wasn’t planning on sharing this recipe yet.
I made this cake for a random Tuesday, no occasion, no guests coming over. Just me testing something out.
Two hours later my neighbor was at my door asking what smelled so good.
That’s when I knew this one was worth writing down properly.
This cake layers soft vanilla sponge with a tart rhubarb compote and a raspberry mousse that’s somehow both light and rich at the same time. 🍰
It looks like something from a bakery window. It’s honestly not that hard to make.
Let’s get into it.
What You’ll Need
Here’s everything you’ll need for this cake, broken into its three parts.
For the vanilla sponge:
- 2 cups all-purpose flour
- 1 ½ cups granulated sugar
- 2 ½ tsp baking powder
- ½ tsp salt
- ¾ cup unsalted butter, softened
- 4 large eggs
- 1 cup whole milk
- 2 tsp vanilla extract
For the rhubarb compote:
- 3 cups rhubarb, chopped
- ⅓ cup granulated sugar
- 1 tbsp lemon juice
- 1 tsp cornstarch
For the raspberry mousse:
- 2 cups fresh raspberries
- 1 cup heavy whipping cream
- ½ cup powdered sugar
- 2 tsp unflavored gelatin
- 3 tbsp cold water
- 8 oz cream cheese, softened
For decoration (optional but pretty):
- Extra fresh raspberries
- A few small mint leaves
- White chocolate shavings
Tools You’ll Need
- Two 8-inch round cake pans
- Stand mixer or hand mixer
- Medium saucepan
- Fine mesh strainer
- Cake turntable (not required, but it helps)
- Offset spatula
- Plastic wrap
- Cake ring or the same 8-inch pans for assembly
Pro Tips (Read Before You Start)
I’ve made this cake enough times to know exactly where people get stuck. Here’s what actually matters:
- Cool your cake layers completely before assembly. Even slightly warm cake will melt your mousse into soup. I usually make the sponge the night before.
- Strain your raspberry puree. Those little seeds are fine in jam, but they’ll mess with the smooth texture you’re going for here.
- Bloom your gelatin properly. Sprinkle it over cold water and let it sit untouched for 5 minutes. Rushing this step is the number one reason mousse doesn’t set.
- Use a cake ring for assembly if you have one. It keeps everything neat while the mousse sets, and you get those clean, sharp layers you see in photos.
- Don’t skip the chill time. I know it’s tempting to slice into it early. Give it the full 4 hours. Your patience gets rewarded here, I promise.
How to Make It
Step 1: Bake the Sponge Layers
Preheat your oven to 350°F and grease two 8-inch cake pans.
Cream the butter and sugar together until it’s light and fluffy, about 3 minutes.
Add the eggs one at a time, mixing well after each one.
In a separate bowl, whisk together the flour, baking powder, and salt.
Add the dry ingredients to the wet mixture in three parts, alternating with the milk. Stir in the vanilla.
Divide the batter evenly between your two pans and bake for 25 to 28 minutes, or until a toothpick comes out clean.
Let the cakes cool in the pans for 10 minutes, then move them to a wire rack to cool completely.
Step 2: Make the Rhubarb Compote
While the cake bakes, combine the rhubarb, sugar, and lemon juice in a saucepan over medium heat.
Cook for about 8 minutes, stirring occasionally, until the rhubarb breaks down.
Mix the cornstarch with a splash of cold water, then stir it into the compote.
Cook 2 more minutes until it thickens, then set it aside to cool.
Step 3: Make the Raspberry Mousse
Puree your raspberries in a blender, then push the puree through a fine mesh strainer to remove the seeds.
Sprinkle the gelatin over the cold water and let it sit for 5 minutes.
Warm the gelatin gently (10 seconds in the microwave works) until it turns liquid, then stir it into the raspberry puree.
In a separate bowl, beat the cream cheese and powdered sugar until smooth.
In another bowl, whip the heavy cream to stiff peaks.
Fold the raspberry puree into the cream cheese mixture, then gently fold in the whipped cream.
Step 4: Assemble the Cake
Place one sponge layer in your cake ring or pan.
Spread the rhubarb compote evenly over the top.
Pour half the raspberry mousse over the compote and smooth it out.
Add the second sponge layer, then top with the remaining mousse.
Smooth the top with an offset spatula.
Refrigerate for at least 4 hours, or overnight if you can wait that long.
Step 5: Decorate and Serve
Once set, carefully remove the cake ring or slide the cake out of the pan.
Top with fresh raspberries, mint leaves, and white chocolate shavings.
Slice with a warm, clean knife for the neatest cuts.
Substitutions and Variations
This cake is pretty flexible once you understand the structure.
- No rhubarb? Swap it for the same amount of chopped strawberries or a mix of strawberries and a little extra lemon juice.
- Dairy-free version: Use a plant-based cream cheese and coconut whipping cream. The texture changes slightly but it still works.
- Gluten-free: A 1:1 gluten-free flour blend works fine in the sponge.
- No fresh raspberries? Frozen raspberries work great for the mousse. Just thaw and drain any excess liquid first.
- Want it boozy? A tablespoon of framboise liqueur in the mousse adds a nice depth for an adults-only version.
Make Ahead Tips
You can bake the sponge layers up to 2 days ahead. Wrap them tightly in plastic wrap and keep them at room temperature.
The rhubarb compote can be made up to 3 days ahead and stored in the fridge.
The full assembled cake actually tastes better the next day, so this is a great dessert to make the day before an event.
Nutritional Breakdown & Extra Details
Here’s roughly what you’re looking at per slice (cake cut into 12 slices):
| Nutrient | Approximate Amount |
|---|---|
| Calories | 380 |
| Fat | 22g |
| Carbohydrates | 40g |
| Sugar | 27g |
| Protein | 5g |
This pairs really nicely with a cup of black coffee or an unsweetened iced tea, since the drink balances out the sweetness of the mousse.
If you’re short on time, bake the sponge the night before and make the compote while the cake cools. That alone saves you almost an hour of downtime.
Leftovers & Storage
Store leftover cake covered in the fridge for up to 4 days.
I don’t recommend freezing this one. The mousse texture changes once it thaws and loses that light, airy quality.
If you want individual slices ready to grab, wrap them separately in plastic wrap before refrigerating.
FAQ
Can I make this as cupcakes instead of a layer cake? You can, though the compote and mousse layering gets trickier at a smaller scale. I’d recommend sticking with the full cake for your first attempt.
Why did my mousse turn out runny? This almost always comes down to the gelatin. Either it wasn’t bloomed long enough or it wasn’t fully dissolved before mixing it in.
Can I use bottled lemon juice instead of fresh? Fresh is better here since it affects both the compote’s flavor and its ability to set properly, but bottled will work in a pinch.
Is this cake very sweet? Not really. The rhubarb adds a nice tartness that balances the sweeter raspberry mousse, so it’s not overly sugary.
How far ahead can I make this for a party? The full cake holds up well in the fridge for up to 2 days before serving, so it’s genuinely a great make-ahead dessert for events.
Wrapping Up
This cake takes a bit of patience, but almost none of it is difficult.
It’s the kind of dessert that looks like you spent all day on it, when really most of that time is just waiting in the fridge.
Make it once and I have a feeling it’ll become your go-to for birthdays, dinner parties, or random Tuesdays that deserve something a little special. 🍓
Try it out and let me know how it goes in the comments below. I’d love to hear what you paired it with, or any twist you added to make it your own.
