Preheat the oven to 175°C . 

Take the butter out of the fridge to allow it to soften. 

1. Melt the butter (in a bain-marie or briefly in the microwave) 
2. Beat all the eggs together with the Zùsto in a mixing bowl.
3. Add the butter in small cubes.
4. Sift the flour and add it to the batter bit by bit.
5. Add the pinch of salt. 
6. Mix everything well with a whisk – there should be no lumps in the batter.
7. Prepare the cake tin: Grease with butter/vegetable oil, add flour or breadcrumbs for a crispy crust. 
8. Pour the batter into the cake tin
9. Bake the mixture for about 40 to 45 minutes in an oven at 180°C. 
10. Check if the cake is done by piercing it with a skewer; if the dough is still wet, the cake needs to stay in the oven a little longer. 

Tip: Take the cake out of the tin to let it cool, so that you get a crispy crust.