Pour the flour into a mixing bowl. Cut the butter into small cubes. Add egg, salt and sugar and knead into a smooth dough with the dough hook of the mixer. Shape the dough into a ball, wrap it in foil and place in the refrigerator for at least 30 minutes.
Rub the peel of a lemon. Squeeze all the lemons.
In a bowl, whip the eggs until creamy, pour in the sugar and whisk to a creamy-white mixture.
Stir in the lemon juice as well as the lemon zest (from just one lemon) and the double crème.
Preheat the oven to 200 ° C.
Now grease a tart form (25 cm diameter) with a little butter.
Roll out the dough on a floured surface and line the mold with it. Prick several times with a fork and prebake for 15 minutes on the middle rack.
Take the pan out of the oven and distribute the filling evenly on the pre-baked base and smooth it out. Bake for another 20 minutes on the same rack at only 180 ° C.
Take out the lemon tart and leave to cool on a wire rack.
To serve, divide into small pieces of cake and dust with a little icing sugar.
The dough can be prepared the day before and stored in foil in the refrigerator until further processing.
This wonderfully fresh lemon tart also tastes great when it is still lukewarm. A scoop of vanilla ice cream rounds off the taste.