Name: No-Bake Blackberry Mousse Tart
Prep time: 10 min
Cook time: 10 min
Total time: 4 h 10 min
Cuisine: American
Ingredients: 28 Oreo Cookies (320 g), or other cookies with cream filling; 1/3 cup vegan butter (80 g), melted; 8 oz blackberries & blueberries (225 g); 1 cup non-dairy cream cheese (225 g), or drained yogurt; 1/3 cup sugar (75 g); 2 tsp vanilla extract; 1 cup non-dairy whipping cream (240 ml), chilled, or coconut cream; 1/4 cup non-dairy milk (60 ml); 1 tsp 100% agar powder, or gelatin powder (if non-vegan)

Jump to Recipe

light and elegant dessert featuring a crisp cookie crust and a silky blackberry mousse, this tart requires no oven time and comes together in under an hour. Perfect for warm-weather gatherings or as a refined finish to any meal.

Why You’ll Love This Recipe

Effortless preparation: No baking required—simply blend, press, and chill.
Vibrant seasonal flavour: Fresh blackberries lend a bright, tangy sweetness.
Make-ahead convenience: Assemble the day before serving for stress-free entertaining.
Impressively elegant: The glossy purple mousse and decorative berry topping look as if you spent hours in the kitchen.

Ingredients

24 Oreo cookies (about 260 g), finely crushed
5 tablespoons unsalted butter (70 g), melted
2 cups fresh blackberries, divided (about 250 g)
2 teaspoons unflavoured powdered gelatin (or 1 envelope), plus 2 tablespoons cold water
8 ounces mascarpone cheese (225 g), room temperature
1 cup heavy whipping cream (240 ml), well chilled
⅓ cup granulated sugar (65 g)
1 teaspoon pure vanilla extract
Pinch of fine sea salt

(Tip: You can find the complete list of ingredients and their measurements in the recipe card below.)

Directions

Prepare the crust. In a medium bowl, combine the crushed Oreo cookies with the melted butter until evenly moistened. Transfer the mixture into a 9-inch (23 cm) tart pan with a removable bottom. Using the back of a measuring cup or a flat-bottomed glass, press the crumbs firmly and evenly across the bottom and up the sides. Chill in the refrigerator while you prepare the filling.
Bloom the gelatin. In a small bowl, sprinkle the gelatin over the cold water and let stand for 5 minutes to soften.
Heat the gelatin. Place the bloomed gelatin in a small heatproof dish and microwave in 10-second intervals, stirring until fully dissolved; set aside to cool slightly.
Blend the berry purée. Reserve ¼ cup of the blackberries for decoration. In a blender or food processor, puree the remaining berries with the sugar, vanilla, and salt until smooth. Strain through a fine-mesh sieve to remove seeds, if desired.
Combine mascarpone and purée. In a large bowl, whisk the mascarpone until smooth. Gradually whisk in the berry purée until fully incorporated.
Whip the cream. In a separate chilled bowl, whip the heavy cream to medium-stiff peaks. Gently fold the whipped cream into the mascarpone-berry mixture until uniform in colour.
Incorporate gelatin. Slowly drizzle the cooled gelatin into the mousse, folding gently to distribute evenly without deflating the mixture.
Assemble the tart. Remove the crust from the refrigerator and pour the blackberry mousse into the chilled shell. Level the top with an offset spatula.
Chill to set. Cover the tart with plastic wrap and refrigerate for at least 1 hour, or until the mousse is firm to the touch.
Decorate and serve. Just before serving, arrange the reserved blackberries on top of the tart. For extra flair, add a few mint leaves or a light dusting of powdered sugar.

Servings and timing

Yield: 8 servings
Prep time: 40 minutes
Chill time: 1 hour (minimum)
Total time: Approximately 1 hour 40 minutes

Variations

Mixed-berry: Replace half of the blackberries with raspberries or blueberries for a colourful blend.
Citrus infusion: Add 1 tablespoon of fresh lemon or orange zest to the mascarpone mixture.
Chocolate crust: Use chocolate wafer cookies in place of Oreos for deeper flavour.
Vegan adaptation: Substitute vegan cream cheese and coconut whipping cream; use agar powder instead of gelatin.
Nutty twist: Press a thin layer of finely chopped toasted almonds or pistachios over the crust before chilling.

Storage/reheating

Refrigerator: Store covered in the refrigerator for up to 3 days.
Freezer: For longer storage, freeze the assembled tart (unwrap tightly) for up to 1 month. Thaw overnight in the refrigerator before serving.
Do not reheat: As a chilled mousse tart, this dessert is best enjoyed cold; reheating will compromise texture.

FAQs

What if I don’t have a tart pan with a removable bottom?

You can use a springform pan or a standard pie dish. A springform pan makes removal easier; in a pie dish, you may serve slices directly without removing the sides.

Can I use frozen blackberries?

Yes. Thaw them fully, then drain or pat dry to remove excess moisture before pureeing, or the mousse may become too watery.

How can I prevent the mousse from weeping?

Ensure that the gelatin is fully dissolved and cooled before adding, and fold gently to preserve the air incorporated by the whipped cream.

Is it possible to make this tart ahead of time?

Absolutely. Assemble and chill the tart up to 24 hours in advance; decorate just before serving to maintain fresh appearance.

Can I substitute gelatin with agar-agar?

Yes, for a vegetarian or vegan version, replace gelatin with agar-agar following package instructions (typically 1 teaspoon agar powder to replace 1 envelope gelatin), heating it in the berry purée.

How to avoid seeds in the mousse?

Strain the blended berry mixture through a fine-mesh sieve or cheesecloth to catch seeds for a smoother texture.

What other cookies work for the crust?

Graham crackers, digestive biscuits, or Biscoff cookies all make excellent no-bake crusts with distinctive flavours.

Can I reduce the sugar?

Yes; taste the berry purée before sweetening and adjust the sugar to your preference. Keep in mind that less sugar may affect the setting slightly.

How tall will the tart be once assembled?

The finished tart will be approximately 1½ inches (4 cm) high, depending on the depth of your tart pan.

How do I slice the tart cleanly?

Use a sharp, hot knife: dip it in hot water, wipe dry, then slice. Repeat between cuts for neat slices.

Conclusion

This No-Bake Blackberry Mousse Tart strikes the perfect balance between simplicity and sophistication. With its velvety mousse, crisp crust, and jewel-like berry garnish, it makes an elegant centrepiece for any occasion. Whether you’re hosting a dinner party or simply craving a light, fruity dessert, this recipe delivers beauty and flavour with minimal effort. Enjoy making—and savouring—this stunning tart!