Cook pasta al dente according to instructions on the packet. Drain and set aside.
Chop the onion and chop the half clove of garlic. Then fry the onion and garlic in a pre-greased pan for 2-3 minutes until they become very lightly coloured.
Add the passata, oregano and salt. Cook over low heat for 5 minutes while stirring regularly. Then pour the passata into a ovenproof dish.
Preheat the oven to 180°C.
For the stuffing
Sauté the spinach for 3-4 minutes in a large frying pan then pour them through a sieve to drain.
Sauté the onion, garlic and pine nuts in a pre-greased pan for 2-3 minutes until very lightly coloured.
Remove the cooled spinach and crush it with your hands to drain completely. Chop it coarsely.
Add the onion, garlic, pine nuts, feta cheese (or tofu), lemon juice, a pinch of salt and pepper. Mix together.
Assembling
Stuff the pasta with the spinach stuffing.
Place the stuffed pasta in the baking dish for baking over the passata.