Preheat oven to 350°F and grease a deep 9×13-inch dish.
Brown beef and sausage with salt and pepper. Drain excess fat.
Add onion, garlic, and 3 tsp seasoning; sauté until soft.
Stir in half the marinara, water, and cream; simmer.
Boil ziti until al dente. Mix with remaining marinara.
In a bowl, mix ricotta, egg, 1 tsp seasoning, and nutmeg.
Assemble layers: meat sauce, half ziti, ricotta mix, cheese, repeat.
Bake uncovered 25–30 minutes until golden and bubbly.
Rest 10 minutes, slice, and serve.
