Making Delicious Zucchini Pizza Casserole is straightforward. Follow these steps for a perfect outcome:

1. Preheat Oven: Preheat your oven to 375°F (190°C).
2. Prepare Zucchini: Slice the zucchinis thinly and place them in a colander. Sprinkle with salt and let them sit for about 10 minutes to draw out excess moisture.
3. Cook Meat: If using, brown the ground beef or Italian sausage in a skillet over medium heat until fully cooked. Drain excess fat and set aside.
4. Layer Zucchini: In a greased 9×13-inch baking dish, layer half of the sliced zucchini evenly across the bottom.
5. Add Sauce and Meat: Spread half of the marinara sauce over the zucchini, followed by half of the cooked meat (if using), and a third of the mozzarella cheese.
6. Repeat Layers: Add the remaining zucchini slices on top, followed by the rest of the marinara sauce, meat, bell peppers, olives, and another third of the cheese. Season with Italian seasoning, garlic powder, salt, and pepper.
7. Finish with Cheese: Top the casserole with the remaining mozzarella cheese.
8. Bake: Cover with foil and bake in the preheated oven for 25 minutes. Then, remove the foil and bake for an additional 10-15 minutes until the cheese is bubbly and golden.
9. Cool and Serve: Once done, let it cool for a few minutes before slicing. Garnish with fresh basil if desired.

These steps will guide you in creating a delicious and satisfying zucchini pizza casserole that everyone will enjoy.