Blueberry Mousse Cake

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This amazing Blueberry Mousse Cake is a soft yellow cake covered with light and airy blueberry mousse.

Blueberry mousse cake on wire rack.

This blueberry mousse cake is a deliciously light cake for fruit lovers. The airy blueberry mousse is so good you will want to eat it by itself.

This is a fantastic recipe for dinner parties or picnics because it’s easy to put together without the fuss of a layer cake. And it’s easy to transport. You can leave it in the pan and cut the slices out.

Unlike my strawberry mousse cake, this recipe is an actual cake. I used my strawberry shortcake cake as the base but baked it in a square pan instead of a round one. The mousse is similar to the mousse for the strawberry version but it makes less so it sits as a thin layer over the cake.

The cake and mousse combined are so light and not overly sweet. It’s all too easy to eat more than one slice.

If you like rich chocolate flavors, try my chocolate mousse cake and Nutella mousse cake as well. It’s supremely decadent.

Why This Recipe Works

  • The yellow cake layer is light, fluffy, and supremely moist. It sticks to your fork!
  • The blueberry mousse is balanced with fresh blueberry flavor and a sweetness that isn’t overpowering.
  • This recipe is adaptable for all sorts of fruity flavors! Just swap equal parts of your favorite fruit for the blueberries. Think, strawberries, pineapples, peaches, mangos, and so much more.
Slice of blueberry mousse cake on wire rack.


For the ingredient measurements and the entire recipe, be sure to scroll down to the bottom of the blog post where the recipe card is located.

  • Butter: Unsalted sweet cream butter will yield the best results for the cake.
  • Sugar: Granulated white sugar is used for the cake and the mousse.
  • Eggs: 2 whole eggs that are at room temperature are needed.
  • Buttermilk: Don’t substitute this! Buttermilk is thick and adds moisture to the cake. Whole milk will not give the same result. And sour cream is too thick.
  • Vanilla: As always, use pure vanilla for the best flavor.
  • Flour: I like cake flour for it’s tight, tender crumb. The results will be different if you use all-purpose flour.
  • Leavening: Baking powder and baking soda work together with the buttermilk to give the cake the perfect amount of rise.
  • Salt: Only a little is needed to balance the sweetness.
  • Blueberries: I prefer fresh blueberries that are in season. They will be sweeter than frozen.
  • Gelatin: 1 packet of unflavored gelatin powder helps to set the mousse.
  • Heavy cream: Look for the label heavy cream or heavy whipping cream. Regular cream will not whip up to stiff peaks.
  • Powdered sugar: Only a small amount is needed to sweeten the cream.

Step by Step Directions

For the full recipe instructions, scroll down to the bottom of the blog post to the recipe card.

  1. Make the cake. Cream the butter and sugar together then mix in the eggs and vanilla. Blend in the buttermilk. Add the flour, baking powder, baking soda, and salt and mix until just combined.
  2. Pour batter into a 9-inch square baking pan and bake until only a few moist crumbs stick to a wooden toothpick. In my oven, it takes 25 minutes.
  1. Make the mousse. Puree blueberries and cook them with sugar until slightly thickened. Stir in gelatin bloomed in water then transfer to a heatproof bowl and refrigerate until completely cooled.
  1. Whip heavy cream, confectioners’ sugar, and vanilla to stiff peaks. Fold in the cooled blueberry mixture.
  2. Spread the mousse over the cake in a lined pan. Refrigerate for a few hours until the mousse is set.

Tips For Success

  • Try to avoid over-baking the cake. This will lead to a dry texture. Start checking for doneness at the 20-minute mark. You’re looking for a few moist crumbs sticking to a wooden toothpick inserted into the center of the cake.
  • When adding the blueberry mixture to the whipped cream, use a gentle folding motion. Being too aggressive will knock the air out of the cream and the mousse won’t be as light and fluffy.
  • Use fresh blueberries that are in season as they tend to be sweeter. This will enhance the flavor of the mousse.
  • Don’t substitute ingredients! The cake has been well-tested and is formulated to yield the softest, moistest texture. Swapping ingredients will give you a completely different result.
Slices of blueberry mousse cake on wire rack.


My blueberry jam mixture didn’t thicken.

That’s perfectly okay! It will not be thick like jam. It will be loose. When folded into the whipped cream and refrigerated, the gelatin will do its job of holding the texture of the mousse.

Can I make the cake ahead of time?

Absolutely! The cake layer can be baked and cooled then wrapped in plastic wrap. Refrigerate or freeze the cake until ready to use. Use within one day of refrigerating or within 30 days of freezing.

Can I make the blueberry jam ahead of time?

Yes, this will be fine. I recommend using it within one or two days though.

Blueberry Mousse Cake

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Blueberry mousse cake on wire rack.
This amazing Blueberry Mousse Cake is a soft yellow cake covered with light and airy blueberry mousse.
Jen Sobjack
Prep Time 25 minutes
Cook Time 20 minutes
Total Time 45 minutes
Serving Size 16


For the cake

  • ½ cup (113 g) unsalted butter, softened to room temperature
  • ¾ cup (150 g) granulated sugar
  • 2 large eggs, at room temperature
  • ¾ cup (180 ml) buttermilk, at room temperature
  • 1 tablespoon vanilla extract
  • 1 ½ cups (180 g) cake flour, sifted
  • 1 teaspoon baking powder
  • ¼ teaspoon baking soda
  • ½ teaspoon salt

For the Mousse

  • 16 ounces (453 g) fresh blueberries
  • 2 ¼ teaspoons unflavored gelatin powder, 1 packet
  • 2 tablespoons water, cold
  • ¾ cup (150 g) granulated sugar
  • 1 ½ cups (360 ml) heavy cream, cold
  • ¼ cup (30 g) confectioners' sugar
  • 1 teaspoon vanilla extract
  • fresh blueberries, for garnish


Make the cake

  • Preheat the oven to 350°F. Lightly grease one 9-inch square pan. Line the bottom with parchment paper then lightly grease the paper. Set aside.
  • In a large bowl, beat the butter and sugar on medium speed until light and fluffy, about 5 minutes.
  • Add the eggs, one at a time, mixing well after each addition. Beat in the vanilla followed by the buttermilk.
  • Combine the flour, baking powder, baking soda, and salt in a medium bowl. Stir with a whisk and add it to the butter mixture. Beat on low speed just until combined.
  • Spread the batter evenly in the prepared pan. Bake for 20-25 minutes, until a toothpick inserted into the center comes out with few moist crumbs attached. Take care to not over-bake or the cake will be dry.
  • Let the cake cool in the pan for 10 minutes then invert onto a wire rack to cool completely.

Make the Mousse

  • Add the blueberries to a blender or food processor and blend to a thin puree.
  • In a small bowl, mix the gelatin and cold water together. Let it sit while you cook the blueberries.
  • In a medium saucepan, combine the blueberry puree and sugar. Cool over medium heat just until it begins to simmer. Reduce the heat to medium-low and cook for 15-20 minutes, until it has reduced slightly.
  • Add in the gelatin and stir until melted and well combined.
  • Pour the blueberry mixture into a heatproof bowl and place in the refrigerator until completely cool, about 1 hour.
  • In a large bowl, beat the cold cream, confectoiners' sugar, and vanilla at high speed until stiff peaks form.
  • Fold in half the cooled blueberry mixture until almost fully combined. Add the remaining blueberry jelly and fold it in until just combined.
  • Line a clean 9-inch square pan with parchment paper, leaving a 1-inch overhang.
  • Place the cooled cake into the pan. Top with the blueberry mousse.
  • Refrigerate for at least 4 hours.
  • Lift the cake out of the pan by the foil overhang and slice into squares. Garnish each slice with fresh blueberries.


  • Cake flour: I don’t recommend substituting the cake flour in this recipe. It offers a tight crumb that’s also very tender and light. You can’t replicate this with any other flour.
  • Buttermilk: If you don’t have buttermilk, you can make it at home. I have a detailed post on how to make homemade buttermilk.
  • Use fresh summer-ripened blueberries for the best flavor. 
Make ahead tip
  1. The assembled cake will keep for up to 3 days stored in the refrigerator.
  2. The cake layer can be made ahead of time. Wrap the cooled layer tightly in plastic wrap and store it at room temperature for up to 2 days, in the refrigerator for up to 5 days, or in the freezer for up to 2 months. Thaw overnight in the refrigerator.
  3. The blueberry jam mixture can be prepared up to 1 day in advance. Cover tightly and refrigerate until ready to use.


Serving: 1slice | Calories: 286kcal | Carbohydrates: 35g | Protein: 4g | Fat: 15g | Saturated Fat: 9g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 4g | Trans Fat: 0.2g | Cholesterol: 65mg | Sodium: 120mg | Potassium: 108mg | Fiber: 1g | Sugar: 25g | Vitamin A: 573IU | Vitamin C: 3mg | Calcium: 48mg | Iron: 0.4mg

The nutrition information provided is for convenience and as a courtesy only. It is not guaranteed to be accurate because nutrition information can vary for a variety of reasons. For precise nutritional data use your preferred nutrition calculator and input the exact ingredients and brands you used in the recipe.

Course: Dessert
Cuisine: American

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  1. Paula Forrester says:

    I haven’t made this recipe yet but it looks and sounds delicious! I would like to know if I can double the ingredients to make a 9×13 size cake?! thank you

    1. Jen Sobjack says:

      I have not attempted to double the recipe yet so I’m uncertain if it’s just as simple as doubling or if any changes need to be made.