Preheat your oven to 375°F (190°C) and grease a baking dish with olive oil.

Slice zucchinis into thin rounds, salt them, and let sit for 10–15 minutes to draw out excess moisture.

In a skillet, sauté diced onion in olive oil until translucent, then add minced garlic and cook until fragrant.

Add ground beef to the skillet and cook until browned, then drain excess fat and stir in tomato sauce, seasoning, and simmer.

Layer zucchini in the baking dish, spread half of the beef mixture, and repeat with remaining ingredients.

Sprinkle shredded mozzarella cheese over the top of the casserole.

Bake in the oven for 25–30 minutes until cheese bubbles and turns golden.

Let the casserole cool for about 5 minutes before slicing and serving warm.