Preheat the Oven to 400°F (200°C).

In a large bowl, combine the shredded zucchini with salt. Let sit for 10 minutes.

Squeeze out excess moisture from the zucchini using a cheesecloth or kitchen towel.

Mix the zucchini with eggs, Parmesan cheese, and half of the mozzarella cheese.

Grease a 9x13-inch baking dish and press the crust mixture evenly into the dish.

Bake the crust for about 20 minutes until set and lightly browned.

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

Stir in pizza sauce, green bell pepper, mushrooms, oregano, garlic powder, and black pepper. Simmer for 5 minutes.

Spread the cooked beef mixture evenly over the baked zucchini crust.

Sprinkle the remaining mozzarella cheese over the beef layer.

Bake for an additional 20 minutes until the cheese is melted and bubbling.

Let the casserole cool for a few minutes before slicing and serving.