Arrange a rack in the middle of the oven and heat the oven to 400°F. Coat a 9x13-inch broiler-safe baking dish with olive oil or cooking spray.

Drain and cut 1 pound fresh mozzarella cheese into ½-inch cubes. Finely grate 2 ounces Parmesan cheese (about 1 cup).

Pour 2 (24-ounce) jars marinara sauce into the baking dish. Add 1 pound dried ziti pasta, the cubed mozzarella, and half the Parmesan cheese. Toss to combine and evenly coat the pasta in the sauce. Dollop 1 container whole-milk ricotta cheese evenly over the mixture and gently stir, keeping a few large pockets of ricotta here and there. Spread the mixture into an even layer and sprinkle with the remaining Parmesan cheese. Cover the dish tightly with aluminum foil.

Bake until the pasta is almost tender but still quite al dente, about 40 minutes. Uncover and continue baking until the pasta is tender, about 20 minutes more. Meanwhile, coarsely chop a few basil or parsley leaves for garnish, if desired.

Switch the oven to broil and broil until the top is browned in spots, 2 to 3 minutes. Let cool for 5 to 10 minutes before garnishing with the basil or parsley, if desired, and serving.