Prep. Preheat the oven to 375˚F. Lightly grease a 9x13 baking dish with cooking spray and set aside.
Prepare the orzo. Cook the orzo according to the directions on the package.
Sauté the zucchini. Meanwhile, heat 1 tablespoon olive oil in a large skillet set over medium heat. Add the zucchini to the heated oil and season with Italian seasoning, ¼ teaspoon salt, and pepper. Cook for 5 minutes, or until the zucchini is crisp-tender.
Combine. Remove the zucchini from the pan and transfer to a large mixing bowl. To the same bowl, add the drained cooked orzo; stir and set aside.
Cook the aromatics. Return the skillet to the burner and heat the remaining olive oil over medium-high heat. Add the onions and cook for 1 minute. Stir in the garlic and cook for 20 seconds.
Cook the beef. Stir in the ground beef, breaking it up with a wooden spoon. Season with the remaining salt and cook for about 6 to 7 minutes, or until the ground beef is completely browned and cooked through. Drain any fat, then transfer the beef to the large bowl with the orzo and zucchini.
Add the remaining ingredients. Stir in the crushed tomatoes, ½-cup mozzarella cheese, ricotta cheese, parmesan cheese, basil, and thyme. Stir until everything is well combined and the cheeses are melted.
Bake. Transfer the mixture to the previously prepared baking dish and top with the remaining mozzarella cheese. Bake for 20 to 25 minutes, or until casserole is bubbly and cheese is melted.
Serve. Remove the casserole from the oven and let it stand for 10 to 15 minutes before garnishing with basil and serving.