Preheat the oven to 375°F
Cook ziti pasta in salted water until al dente
Drain the pasta
Brown ground beef or Italian sausage in a skillet
Add chopped onion and garlic and cook until softened
Stir in marinara sauce and simmer briefly
Mix ricotta cheese, egg, grated Parmesan, salt, and pepper in a bowl
Combine the cooked pasta with the meat sauce
Spread a layer of sauce in a baking dish
Add half the pasta mixture
Spoon dollops of the ricotta mixture over the pasta
Sprinkle with mozzarella cheese
Add the remaining pasta mixture
Top with more mozzarella and Parmesan
Cover with foil and bake for 20 minutes
Remove foil and bake for 10 to 15 minutes until bubbly and golden
Let rest for 10 minutes before serving