Step 1: Prep Oven and Pasta
Preheat oven to 350°F.
Bring large pot of salted water to a boil.
Boil ziti for 8 minutes (al dente). Drain and reserve 1/4 cup of pasta water.
Step 2: Cook Meat (Skip for Vegetarian)
Brown meat in skillet with onion until no longer pink.
Add garlic at the end, cook 1 minute.
Drain excess fat.
Step 3: Mix Ricotta Layer
In bowl, mix ricotta, 1.5 cups mozzarella, egg, parsley, salt & pepper.
Step 4: Assemble
In baking dish, spread thin layer of sauce.
Mix half of ziti with some sauce, layer on bottom.
Spread ricotta mixture over ziti.
Add rest of ziti and remaining sauce.
Top with remaining mozzarella and all the parmesan.
Step 5: Bake
Cover loosely with foil.
Bake 20 minutes.
Remove foil, bake 10–15 minutes more until cheese is golden.
Rest for 10 minutes before serving.