Slice zucchini into ½-inch rounds. Place in a colander, sprinkle with salt, and toss. Let sit for 15 minutes to draw out moisture.

Rinse zucchini under cold water to remove excess salt. Pat dry with paper towels.

Heat olive oil in a large skillet over medium-high heat. Add onion and cook for 2 minutes until softened.

Stir in garlic and cook briefly until fragrant.

Add ground beef and cook, breaking it apart, until browned and no pink remains (about 5 minutes).

Stir in Italian seasoning, salt, pepper, and drained tomatoes. Mix well and cook for 2–3 minutes. Remove from heat.

Preheat oven to 350°F (175°C). Lightly grease an 8×8-inch baking dish.

Spread half of the beef mixture on the bottom. Layer with half the zucchini slices, then half the mozzarella.

Repeat layers with remaining beef, zucchini, and cheese.

Bake for 20–25 minutes until cheese is melted and golden brown.

Remove from oven and let rest for 10 minutes before serving.