Slice zucchini lengthwise into ⅛-inch thick strips, sprinkle with salt, and let rest for 20–30 minutes to draw out moisture. Pat dry with paper towels.

In a large skillet, heat olive oil over medium heat. Sauté onions until translucent, about 5 minutes, then add garlic for 1 minute. Add ground beef or sausage, cooking until browned for 7-10 minutes.

Stir in crushed tomatoes, tomato paste, and seasonings. Let the sauce simmer for 15–20 minutes until thickened.

In a mixing bowl, combine ricotta cheese, egg, Parmesan cheese, and parsley. Mix until well blended.

Preheat oven to 375°F (190°C). In a baking dish, layer meat sauce, zucchini, cheese mixture, and mozzarella. Repeat layers, finishing with meat sauce and mozzarella on top.

Cover with foil and bake for 30 minutes. Remove the foil and bake for an additional 10–15 minutes until golden and bubbly.

Let rest for 10–15 minutes before serving. Garnish with fresh basil or parsley.