Preheat your oven to 400°F (200°C).

Grate zucchini and sprinkle with salt. Let sit in a colander for 10 minutes.

Squeeze out as much liquid from the zucchini as possible.

Combine drained zucchini, eggs, Parmesan cheese, and half of the mozzarella in a bowl. Mix until thick and creamy.

Grease a 9x13-inch baking dish and press the zucchini mixture into the bottom.

Bake for 20 minutes, or until the crust is set and lightly golden.

In a skillet, cook the ground beef and onion over medium heat until browned. Drain excess fat.

Stir in pizza sauce, bell pepper, mushrooms (if using), oregano, garlic powder, and black pepper. Simmer for 5 minutes.

Spread the beef mixture over the baked zucchini crust.

Sprinkle remaining mozzarella and cheddar cheese over the beef mixture.

Bake again for 20 minutes until cheese is melted and bubbly.

Let cool for a few minutes before slicing and serving.