Baked Pasta with Sardines in Tomato Sauce

1. Cook the pasta al dente and drain.
2. Heat the olive oil in a pan, add the chopped onion and garlic, and sauté briefly.
3. Stir in the passata, sardines in tomato sauce, and seasonings. Cook over low heat for 5 minutes.
4. Combine the pasta with the sauce and transfer to a baking dish.
5. Sprinkle the mozzarella and grated cheese on top.
6. Bake for 15 minutes at 200 °C until the cheese melts and turns golden.
7. Serve warm, garnished with a fresh basil leaf and a slice of lemon.