No-Boil Method: Place the dried ziti in a large bowl. Add a generous spoonful of salt and fill the bowl with very hot tap water. Stir well, then allow the pasta to soak for 20-25 minutes. (You can also boil the pasta according to package instructions.)
Meanwhile, preheat the oven to 400 degrees F. Set out a 9 X 13 inch (3 quart) baking dish. Set a large sauté pan over medium heat.
Add the diced pancetta to the sauté pan. Move it around the pan to brown for 3 minutes. Then add the sausage. Stir and break the sausage into small pieces, cooking another 3 minutes. Finally, add the onions and garlic. Sauté for another 3-5 minutes to soften.
Once the onions are soft, stir in the marinara, basil, parsley, and crushed red pepper. Turn the stovetop to low and allow the sauce to simmer for 5-10 minutes, while you make the ricotta filling.
In a medium bowl, combine the ricotta, half the mozzarella, half the parmesan, eggs, 1/4 teaspoon salt, and 1/4 teaspoon black pepper. Mix well.
Once the ziti has soaked for at least 20 minutes, drain off the water and pour the drained ziti into the simmering meat sauce. Mix well and turn off the heat.
Scoop half the ziti and sauce into the baking dish. Spread into an even layer. Then spoon the ricotta mixture over the ziti. Spread the ricotta to cover the ziti. Then top the ricotta with the remaining ziti and sauce. Sprinkle the top of the ziti with the remaining mozzarella and parmesan cheese.
Cover the dish with foil. Bake for 25 minutes. Then take the foil off the top and bake uncovered for another 10 minutes. Serve warm.
Slow Cooker Baked Ziti Instructions: If desired, you can make this recipe in a crockpot. You do not need to boil or soak the ziti beforehand. However, you do still need to make the sauce on the stovetop. Add 3/4 cup water to the sauce when you add the ziti, so there is plenty of moisture for the pasta to absorb. Then assemble the ziti in a large slow cooker, and cook on low for 3-5 hours.