Preheat the oven to 375 degrees, and grease a 9×13-inch baking dish.

Dice your onion and slice the zucchinis.

Add the ground beef to a large skillet, and cook over medium heat, until browned, breaking it up as it cooks.

Add the onion and garlic, and continue cooking for about a minute. Stir the sauce and seasonings into the meat mixture. Set aside.

Arrange the zucchini slices in rows in a 9x13 inch casserole dish, slightly overlapping each other.

Pour the meat and sauce over the zucchini, then sprinkle with mozzarella.

Bake uncovered for 20 minutes..

Sprinkle with fresh parsley, and allow the casserole to stand for 5 minutes before serving.