Step by step

After adding the egg, mix well until you obtain a smooth consistency. Shape into a ball and leave to rest in the fridge for half an hour.

Tips
Have you ever inadvertently caramelised the jam when making a tart? To avoid this problem, add a pinch of flour to the jam before spreading it on the pastry dough.
Trivia
According to legend, the origin of the tart is to be found in a mythological event whereby the siren Parthenope was rejected in love by Ulysses: she was given some ingredients by the people, and then offered them to the gods. The latter made them into a tart which was then given back as a gift to the people who had originally donated the ingredients.