In a large frying pan add 4 tablespoons of extra virgin olive oil and let the oil warm up a little when it is hot, add the finely chopped onion and let it brown, then add the Passata or peeled tomatoes in the pan, a pinch of salt, a few basil leaves and cook for 20-30 minutes.
Boil a pot with plenty of salty water for the gnocchi, they will take not more than 3/5 minutes to cook
When they start to float they are done, just take them using a kitchen spider or something similar
Drain the gnocchi and pour them in the pot and add a few ladles of tomato sauce and a few pieces of fior di latte mozzarella.
Turn it well with a ladle and melt the mozzarella and mix it well
Pour the gnocchi into a terracotta tray or oven deep tray pan, according to the portions Add the tomato sauce, grated cheese, provolone or mozzarella cut into pieces and bake for about 15 minutes at 180 C. degrees.
Serve the dish with some fresh basil leaves