Preheat your oven to 375°F (190°C).

In a skillet over medium heat, add olive oil, then cook the ground beef until browned, typically about 5-7 minutes. Drain the excess fat.

Mix in salt, pepper, and Italian seasoning, then stir in marinara sauce and let it simmer for a few minutes.

In a 9x13 baking dish, layer half of the sliced zucchini on the bottom. Pour half of the ground beef mixture over the zucchini, then sprinkle a generous layer of mozzarella cheese on top.

Add another layer of zucchini, followed by the remaining ground beef mixture and top with the rest of the mozzarella and grated Parmesan cheese.

Cover the baking dish with foil to prevent it from over-browning, and bake in the preheated oven for 20 minutes. Remove the foil and bake for an additional 5-10 minutes, until the cheese is bubbly and golden.

Let it cool for a few minutes, then slice and enjoy your delightful cheesy zucchini bake.