Crush the biscuits in a food processor and mix with the melted butter. Press the mixture into the bottom of a springform pan lined with parchment paper.

Place the base in the refrigerator for 30 minutes to set.

Soak the gelatin sheets in a large bowl of cold water for about 10 minutes.

Rinse the strawberries and raspberries, reserving a few for decoration. Blend the remaining fruits with lemon juice and strain the puree through a sieve to remove the seeds.

Heat half of the strained fruit coulis in a saucepan with the sugar over medium heat. Remove from heat, add the 4 squeezed gelatin sheets, and stir until fully dissolved.

Mix in the remaining cold fruit coulis and allow it to cool slightly.

In a separate bowl, whip the very cold cream until it forms stiff peaks.

Gently fold the lukewarm fruit coulis into the whipped cream using a spatula.

Pour the mousse over the chilled biscuit base and smooth the top. Refrigerate for 2 hours until set.

Heat the remaining fruit coulis and dissolve the last 2 gelatin sheets off the heat.

Let it cool to room temperature before carefully pouring it over the set mousse.

Leave to set in the refrigerator for at least 4 hours or ideally overnight.

When ready, delicately unmold the bavarian cream and garnish with the reserved fresh fruits and mint leaves.

Slice the Bavarian cream into wedges and serve on elegant dessert plates.