Step by step

Place the flour on a pastry board, make a well in the centre and add the eggs and softened butter in pieces.

Tips
If you are a fruit lover, you could replace the principal ingredient, Nutella, with a nice chestnut puree.
Trivia
The tart is a dessert which some claim originated in Italy, widespread across many of its regions, and now there are many new interpretations and revisitations of the basic approach across Europe.