Process the flour with 75g Parmesan, the butter, an egg and a little salt to make a smooth shortcrust pastry. This works best with a dough hook and later with your hands.
Cover and chill for about 30 minutes.
Wash and halve the tomatoes. Mix the sour cream and the remaining 3 eggs and season everything well. Now stir in the remaining 75g of the parmesan and the basil.
Line a 26 cm diameter mold with parchment paper. Roll out the dough on a floured surface and place in the mold, pressing the edge approx. 2 cm high. Prick the bottom several times with a fork.
Add the tomatoes and spread about 2/3 of the ham cut into small pieces.
Pour the sour cream mixture over it and cover with the rest of the ham.