Crumble the Italian sausage (or ground beef) into a large pot set over medium-high heat. Cook, drain, and push meat to the edges of the pot. Drizzle the oil in the center of the pot and add the garlic, stirring and cooking for about a minute or until fragrant and beginning to turn light golden brown. Stir int the tomatoes with juices, tomato sauce, herbs, and garlic powder. Bring to a boil, stirring occasionally. Reduce heat to low, cover, and simmer for 10 minutes.
While sauce is cooking, preheat oven to 400°F. Simultaneously, bring a large pot of salted water to a boil on the stove over high heat. Cook the ziti until just al dente (do not overcook). Drain and set aside.
After sauce has simmered for 10 minutes, taste and stir in enough sugar to counter the acidity of the tomatoes. Season sauce to taste with salt, freshly ground black pepper, and crushed red pepper flakes (if using). If desired, add more herbs (particularly if using fresh herbs).
Stir the cooked ziti into the marinara sauce. Mix in ricotta cheese and grated mozzarella. Pour pasta into a 4 1/2 to 5-quart baking dish (I use a large rectangular baking dish that's slightly larger than a 9x13). Top with sliced fresh mozzarella and sprinkle with grated Parmesan. Bake until golden brown and bubbly, about 20 to 30 minutes.
If using Italian sausage, you may use sweet, spicy, or a half pound of each.
If available, you may substitute 3 tablespoons chopped fresh Italian herbs (such as a combo of basil, oregano, thyme, and/or parsley) for the dried herbs.
If you wish, you may use all fresh mozzarella or all regular mozzarella in this recipe. Fresh mozzarella is more expensive, so I typically use regular mozzarella for grating and stirring into the pasta. Then I top the dish with sliced fresh mozzarella to make the flavor and presentation more special. If you wish to use fresh mozzarella mixed into the pasta, just cut it into small cubes (since it's too soft to be grated).
You can probably squeeze the pasta mixture into a regular 9- by 13-inch baking dish, but the fit may be snug. I prefer using a DEEP baking dish just to be safe, or I divide the pasta between two 8- by 8-inch baking dishes, cooking one now and freezing one for later.
Two (24-ounce) jars of store-bought marinara may be substituted for the homemade sauce.