First prepare the shortcrust pastry: combine cold butter pieces and flour in a mixer and blend, then transfer the mixture into a bowl, add sugar, lemon and egg yolk and work quickly until you obtain a homogeneous dough: wrap with cling film and leave rest in the fridge for at least 30 minutes.

Take the dough and roll it out into a thin sheet (about 0.5 cm), then place it in the buttered and floured mold and smooth the edges.

Prick the bottom with the tines of a fork and proceed with cooking in white: cover with a sheet of baking paper and then with dried legumes, then cook for about 30 minutes in a static oven preheated to 180°C.
Remove from the oven, remove the legumes and baking paper and cook for another 5 minutes, then remove from the oven and leave to cool completely.

Start preparing the cream for the filling: soak the isinglass in cold water.

Meanwhile, squeeze the lemon juice and then filter it.
Place raspberries (200 g) and lemon in a suitable container and blend with the blender, then filter again.

Combine mascarpone cheese, 75 g of cream and sugar in a bowl and whip until obtaining a homogeneous mixture, then also add the raspberry puree and mix.

Heat the remaining cream (25 g) in a saucepan, add the drained and gently squeezed gelatine and mix until it dissolves.
Incorporate the mixture thus obtained into the cream, mixing until a uniform mixture is obtained.

Assemble the tart: place the base on a serving plate, pour in the cream and level the surface well, then decorate with the remaining fresh raspberries (250g).

The raspberry tart is ready, all you have to do is serve it.