Strawberry Mousse Recipe

Prepare and bake cake

Preheat the oven to 350°F (175°C). Lightly grease and line the base of an 8-inch (20 cm) round cake pan with parchment. In a medium bowl whisk together 1 1/4 cups all-purpose flour, 1 tablespoon granulated sugar, 1 teaspoon baking powder and 1/4 teaspoon salt until combined.

In a separate bowl whisk 1/2 cup whole milk, 1 large egg, 3 tablespoons melted cooled butter and 1 teaspoon vanilla extract until smooth.

Add the wet ingredients to the dry ingredients and stir gently until just combined — do not overmix. Scrape batter into the prepared pan and smooth the top.

Bake in the preheated oven for 18–22 minutes, or until the top is lightly golden and a toothpick inserted into the center comes out clean. Remove from oven and cool in the pan for 10 minutes, then transfer to a wire rack to cool completely. Once cooled, if needed, level the cake top with a serrated knife so it sits flat for the mousse layer.

Prepare strawberry purée

Place 12 oz hulled and chopped strawberries and 3 tablespoons granulated sugar in a blender or food processor. Add 1 teaspoon fresh lemon juice. Purée until smooth (about 30–45 seconds). Taste and adjust sugar if necessary.

Strain the purée through a fine-mesh sieve into a bowl, pressing with the back of a spoon to extract as much liquid and remove seeds. You should have roughly 3/4 to 1 cup purée. Chill briefly if warm.

Bloom gelatin

Sprinkle 1 teaspoon unflavored powdered gelatin evenly over 2 tablespoons cold water in a small heatproof bowl. Let stand 3–5 minutes to bloom.

Gently warm the bloomed gelatin (either over a small pot of simmering water or 8–10 seconds in the microwave) until it is liquid and just warm — do not boil. Stir 2–3 tablespoons of the chilled strawberry purée into the liquid gelatin to temper, then whisk the gelatin mixture back into the rest of the purée until fully combined.

Whip cream

In a chilled mixing bowl, combine 1 1/2 cups cold heavy cream, 2 tablespoons confectioners' sugar, 1/2 teaspoon vanilla extract and a pinch of salt. Using a hand mixer or stand mixer with the whisk attachment, whip on medium-high speed until soft-medium peaks form (peaks should hold but be slightly soft).

Take about one quarter of the whipped cream and fold it into the strawberry purée (with gelatin) to lighten it — use a rubber spatula and gentle folding strokes to preserve air. Then fold in the remaining whipped cream until homogeneous and no streaks remain. Do not overfold; stop when the mousse is uniform and airy.

Assemble

Place the cooled vanilla cake layer on a serving plate. If cutting into individual portions or using a ring, set a cake ring or acetate collar around the cake. Spoon or pipe the strawberry mousse evenly over the cake to a thickness of about 1 to 1 1/2 inches. Smooth the top with an offset spatula.

Refrigerate the assembled cake for at least 3 hours, preferably 4–6 hours, until the mousse is set. For best texture, refrigerate overnight. Keep covered to prevent absorbing fridge odors.

Before serving, remove the cake ring or acetate. Arrange fresh strawberry slices and mint leaves on top. Lightly dust with 1/2 teaspoon powdered sugar just before serving.

Slice with a sharp knife dipped in hot water and wiped dry between cuts for clean slices. Serve chilled.