Sieve the flour with a pinch of salt, pile it up on your work surface and create a “well” in it. In the centre put the softened butter (you should take it out of the fridge half an hour beforehand), the egg and egg yolk, the sugar and grated peel of the lemon. Delicately mix the ingredients, first with a fork and then with your hands (if possible “cold”), without working the dough too much so that the pastry will be crumbly. Shape it into a ball, sprinkle lightly with flour, put it in a bowl, cover and leave to rest in a cool place for at least half an hour.
In the meanwhile move on to the filling. The gelatine should be added to the pastry cream while it’s still hot: soak the leaves of gelatine for 10 minutes, then strain and squeeze them well with your hands; put them on the stove in a small saucepan and stir with your index finger – the gelatine will dissolve quickly, before your finger burns! Stir it into the pastry cream until completely incorporated, then cover the surface to prevent a “skin” forming as it cools.
Now take your shortcrust pastry, lightly dust your work surface and the dough with flour, and use a rolling pin to roll it out to a thickness of 3-4 mm. Take care because it breaks easily. Use it to line a well-buttered, non-stick tart tin, leaving a high edge because it will contain the pastry cream and strawberries (if you have problems rolling out the pastry dough with a rolling pin, spread it out directly in the tin, flattening it with your hands). Prick the pastry here and there with a fork, to prevent it from rising up during cooking, and cover the bottom with a sheet of kitchen foil and some dried beans, or rice, to weigh it down. Put it in a preheated oven at about 150 °C, bake it for 30 minutes covered and then for another 5-10 minutes without the foil, so that the pastry turns a nice biscuit colour all over; then remove it from the oven. When it has cooled down, sprinkle icing sugar – sifted through a tea strainer – around the outer edge (which is never very neat and tidy), and fill the tart with the pastry cream, levelling the surface well.
While the tart base is in the oven, wash the strawberries (they should be ripe but firm and not too large), remove the stalk and leafy part, and leave them to marinate for 30 minutes with 2 spoonfuls of cane sugar. Strain them and dry them with kitchen paper (otherwise they will stain the pastry cream). Cut them in half, arrange them in concentric circles on top of the pastry cream and brush them with gelatine glaze (or with strawberry jam, heated and put through a strainer), taking care not to touch the pastry cream with the brush.
Your tart is finally ready!!! It may be slightly lengthy to prepare, but it will reward you (or at least we hope so) with its colourful appearance and delicious taste. Don’t forget to keep it in the fridge once it has cooled right down.