Use leftover pasta or cook dry pasta al dente. Drain well.
Heat a large skillet. Add pasta, tomato sauce, tomato paste, oregano. Stir well to coat the spaghetti with the sauce. Heat well, especially if the pasta was cold.
Add grated Parmesan and cubed mozzarella. Stir well until the cheese is melted.
Adjust the taste with salt and pepper, sprinkle with herbs, and serve immediately.
Notes
Or any other type of pasta.
Use homemade or your favorite brand.
You can use other sorts of cheese instead. For instance, Cheddar, Gouda, or anything else you like.
What you could add: onion, garlic, bacon, cooked chicken, canned tuna, peas, canned artichokes, baby spinach, green onions, and so on. See the blog post for more suggestions.