Pin The first time I made this cake was actually by accident. I had planned to make a simple lemon tart but found myself with an abundance of fresh blueberries from the farmers market. The kitchen smelled incredible while the shortbread crust baked, that buttery golden scent filling every corner. Something about the combination of tangy lemon and sweet blueberries just felt right, like they were always meant to be together. It has become my go-to dessert for summer gatherings ever since.
I brought this to a Fourth of July party last summer and watched it disappear within minutes. My friend Sarah who claims she does not even like dessert went back for seconds. There is something about those vibrant purple swirls against the pale yellow mousse that makes people instinctively reach for a slice before you have even finished serving.
Ingredients
- 1 1/2 cups all-purpose flour: The foundation of our shortbread crust. Do not be tempted to swap this for whole wheat or the buttery delicate texture will suffer.
- 1/2 cup powdered sugar: Powdered sugar contains cornstarch which helps create that melt in your mouth shortbread texture regular sugar cannot achieve.
- 1/2 cup unsalted butter cold and cubed: Keeping the butter cold is crucial for a flaky crust. Cut it into small cubes right before using and work quickly.
- Pinch of salt: Just enough to make the butter flavor sing without tasting salty.
- 1 cup heavy cream: Gives the mousse its luxurious silky texture. Make sure your cream is very cold before whipping.
- 1/2 cup granulated sugar: Sweetens the mousse while letting the bright lemon flavor remain the star.
- Zest of 2 lemons: Use a microplane to get just the yellow outer layer. The white pith underneath tastes bitter.
- 1/2 cup fresh lemon juice: Room temperature lemons yield more juice. Roll them on the counter before cutting to break down the fibers.
- 1 tablespoon gelatin powder: This is what gives the mousse structure so it holds its beautiful layers when sliced.
- 2 tablespoons water: Blooming the gelatin properly ensures it dissolves evenly without any lumpy bits.
- 8 ounces cream cheese softened: Use full fat cream cheese and let it come to room temperature completely for the smoothest mousse.
- 2 cups fresh blueberries: Look for berries that are deeply colored and slightly dusty. That natural bloom indicates freshness.
- 1/4 cup granulated sugar: Just enough to draw out the blueberry juices without masking their natural flavor.
- 1 tablespoon fresh lemon juice: A splash of acid brightens the compote and helps the blueberry flavor really pop.
Instructions
- Preheat and prepare your pan:
- Set your oven to 350°F and line an 8-inch springform pan with parchment paper. This will make removing your beautiful cake effortless later.
- Make the shortbread crust:
- Pulse flour powdered sugar cold butter and salt in a food processor until you see coarse crumbs. Press the mixture firmly into the bottom of your prepared pan in an even layer.
- Bake the crust:
- Bake for 20 to 25 minutes until the edges are golden brown. Let it cool completely before adding any filling otherwise the mousse will melt.
- Prepare the blueberry compote:
- Combine blueberries sugar and lemon juice in a saucepan over medium heat. Cook for about 10 minutes until berries burst and the mixture thickens beautifully. Set aside to cool completely.
- Bloom the gelatin:
- Sprinkle gelatin over water in a small bowl and let it sit for 5 minutes. This softens the granules so they dissolve smoothly later.
- Dissolve the gelatin:
- Warm the lemon juice in a small saucepan then stir in the bloomed gelatin until completely dissolved. Let it cool to room temperature before the next step.
- Beat the cream cheese mixture:
- In a large bowl beat the softened cream cheese with sugar and lemon zest until you have a perfectly smooth creamy base.
- Whip the heavy cream:
- In a separate bowl whip the cold heavy cream until stiff peaks form. Do not overwhip or it will become grainy.
- Combine the mousse:
- Beat the cooled gelatin mixture into the cream cheese until smooth then gently fold in the whipped cream. Take your time here to keep it light and airy.
- Layer the cake:
- Spread half the lemon mousse over the cooled crust. Dollop half the compote on top and swirl gently with a knife. Repeat with remaining mousse and compote for those gorgeous ribbons of purple.
- Chill until set:
- Refrigerate for at least 4 hours or overnight. The gelatin needs time to firm up so each slice holds its shape perfectly.
- Serve and enjoy:
- Release the springform ring and slice with a sharp knife wiped clean between cuts. Garnish with fresh berries if you like.
Pin My grandmother always said that desserts made with love taste better and I think about that every time I make this cake. The way the blueberry compote ripples through the lemon mousse reminds me that the best things in life are often the most unexpected combinations. It has become a tradition at our family summer table.
Make Ahead Magic
You can prepare the crust up to two days in advance. Wrap it tightly in plastic wrap once completely cooled and store at room temperature. The blueberry compote also keeps beautifully in the refrigerator for up to five days. This means you can break up the preparation and avoid any last minute stress before your gathering.
Swirl Like a Pro
Getting those gorgeous purple ribbons is easier than it looks. Drop the compote in small dollops across the mousse rather than spreading it. Then use a butter knife to gently swirl through the layers in a figure eight motion. Do not overwork it or you will lose the distinct marbling effect that makes this cake so stunning.
Serving Suggestions
This cake needs nothing else to shine but a few thoughtful extras can elevate it even further. A dollop of lightly sweetened whipped cream adds extra luxury. Fresh mint leaves bring a pop of green color that looks gorgeous against the purple and yellow.
- Let the cake sit at room temperature for 15 minutes before serving so the mousse softens slightly
- Use a hot knife dipped in hot water and wiped dry between slices for perfectly clean cuts
- Store any leftovers covered in the refrigerator for up to three days though the texture is best on day one
Pin Every time I serve this cake someone asks for the recipe. There is something about those layers of bright sunshine flavors that just makes people happy. Hope it brings as much joy to your table as it has to mine.
Recipe Q&A
- → How long should I chill the mousse cake?
Refrigerate for at least 4 hours until completely set. For best results, chill overnight to allow all layers to firm up properly and flavors to meld together.
- → Can I make this dessert ahead of time?
Yes, this cake actually benefits from being made 1-2 days in advance. The extended chilling time helps the mousse set firmly and allows the blueberry compote to fully infuse its flavor throughout the layers.
- → What other berries can I use instead of blueberries?
Raspberries, blackberries, or a mixed berry blend all work wonderfully. Each berry will bring its own unique flavor profile—raspberries add brightness while blackberries offer deeper, earthier notes.
- → How do I know when the gelatin is fully dissolved?
Heat the gelatin mixture gently over low heat while stirring constantly. You'll know it's dissolved when the liquid becomes completely clear with no visible granules or cloudiness remaining.
- → Can I use frozen blueberries for the compote?
Frozen blueberries work perfectly for the compote. They may release more liquid than fresh, so simply cook for a few extra minutes until the mixture reaches your desired thick, jammy consistency.
- → Why did my mousse not set properly?
This usually happens if the gelatin mixture was too hot when added to the cream cheese, causing it to seize, or if it wasn't fully dissolved. Always let the gelatin cool to room temperature before incorporating.