Pour the biscuit mixture into the tart pan - press the sides and bottom of the pan thoroughly.

Wash and dry the fruit for the mousse, peel if necessary, cut into smaller pieces and blend thoroughly with a blender.

Add quark cheese and sugar to the blended fruit - blend together.

Cover the gelatin with cold water - just enough to cover its surface.

Once the gelatin swells, heat it briefly in the microwave until it becomes liquid.

Whip the cold heavy cream until thick.

Add the whipped cream to the fruit mixture and gently mix.

Add 1-2 tablespoons of the fruit mixture to the gelatin and mix, then pour the gelatin into the rest of the mixture - mix thoroughly.

Pour the mousse onto the biscuit crust.

Place the pan in the refrigerator for several hours - for the mixture to set.