Preheat the oven to 375°F (190°C).
Slice the zucchini thinly and salt them. Let them sit for 10 minutes to draw out excess moisture.
Brown the ground beef in a large skillet and drain excess fat.
Add tomato sauce, garlic powder, Italian seasoning, salt, and pepper to the beef and let simmer for 5-10 minutes.
In a separate bowl, mix ricotta, mozzarella, Parmesan, and the egg until smooth.
In a greased 9x13 baking dish, spread a thin layer of meat sauce.
Add a layer of zucchini on top, followed by half of the cheese mixture.
Repeat with another layer of sauce, zucchini, and cheese mixture.
Finish with zucchini and top with mozzarella cheese.
Cover with aluminum foil and bake for 30 minutes, then uncover and bake for an additional 10-15 minutes until golden and bubbly.
Let cool for 10 minutes before slicing and serving.