Preheat the oven to 350°F / 180°C. Cook 300g of ziti for 1 minute less than the package directions. Reserve some cooking water, then drain.
Mince 4 garlic cloves and measure 2½ cups of shredded mozzarella. Squeeze 350g of thawed frozen chopped spinach dry.
Mix the spinach with 500g of ricotta, ½ cup of grated Parmesan, half the garlic, two-fifths of the mozzarella, ¾ teaspoon of salt and ¾ teaspoon of black pepper. Loosen with a splash of cooking water.
Mix 700g of tomato passata, 1 tablespoon of olive oil, the remaining garlic, 1 teaspoon of onion powder, 1 teaspoon of garlic powder, 2 teaspoons of dried Italian herbs, 1 teaspoon of sugar, and 1 teaspoon of salt.
Toss the pasta with the ricotta mixture and spread in a shallow baking dish. Cover with the tomato sauce and remaining mozzarella.
Loosely cover with foil and bake for 25 minutes. Uncover and bake for 10 minutes, until bubbling and the cheese melts.
