Begin by preheating your oven to 375°F and preparing your ingredients for assembly. In a large skillet over medium-high heat, brown 2 lbs of extra lean ground beef, breaking it apart as it cooks until it’s fully cooked through, approximately 8-10 minutes.

While the beef cooks, dice 1/2 large white onion and add it to the pan along with 2 teaspoons of minced garlic, allowing these aromatics to soften and infuse their flavors into the meat for about 2 minutes.

Once the beef is cooked, drain any excess fat if necessary, then stir in 3 large chopped tomatoes, 1 tablespoon of dried basil, 1 teaspoon of dried oregano, 1/4 teaspoon of ground nutmeg, 1 tablespoon of salt, and 1/4 teaspoon of black pepper. Let this mixture simmer for 5 minutes to guarantee the flavors meld together.

While the beef mixture simmers, prepare 2 large zucchini by slicing them lengthwise into thin strips or rounds, depending on your preference. In a 9×13 inch baking dish, layer half of the zucchini slices on the bottom, then spread half of the cooked beef mixture over them.

Add the remaining zucchini slices as the next layer, followed by the rest of the beef mixture. Top the entire casserole with 1 1/2 cups of fat free mozzarella cheese, distributing it evenly across the surface to confirm every portion gets melted cheese coverage.

Cover the baking dish with aluminum foil and bake for 25-30 minutes, until the zucchini is tender when pierced with a fork.

Remove the foil during the last 5 minutes of baking to permit the cheese to brown slightly and develop a light golden crust. Let the casserole rest for 5 minutes after removing it from the oven before serving, which allows the layers to set slightly for cleaner portions and easier serving.