• Add the ground beef, onion and red bell pepper to a 12-inch oven-safe skillet over medium-high heat. Cook, breaking the beef apart as it browns.

  When the beef is about halfway browned, add the Italian seasoning, salt, mixed pepper and crushed red pepper, if using. Continue cooking until the beef is browned and the vegetables have begun to soften. Drain excess grease if necessary.

  Add the garlic and cook for about 30 seconds. Stir in the uncooked rice and cook for 1–2 minutes, stirring frequently, to lightly toast the rice and coat it in the seasoned beef mixture.

  Pour in the marinara and beef stock. Stir well, scraping the bottom of the skillet to loosen any browned bits. Bring the mixture to a gentle boil, then reduce the heat to low and cover. Simmer for 10 minutes.

  Stir in the zucchini. Cover and continue cooking for 8–10 minutes, or until the rice is almost tender. Turn off the heat and leave the skillet covered for 5 minutes. The trapped steam will finish cooking the rice and allow it to absorb the remaining sauce.

  Uncover and check the rice. If it is still noticeably firm, add a small splash of beef stock and cook it over low heat, covered, for another 2–3 minutes.

  Remove the skillet from the heat. Stir in 1 cup of the mozzarella and ½ cup of the Parmesan. Taste and adjust the salt and pepper as needed.

  Sprinkle the remaining 1 cup mozzarella and ½ cup Parmesan over the top. Place the skillet under the broiler for 2–4 minutes, watching closely, until the cheese is melted, bubbling and browned.

  Let the skillet rest for 5 minutes before serving.

Notes

• Use a 12-inch oven-safe skillet so there is enough room for the rice to cook evenly and the zucchini to remain in distinct pieces.

  Cut the zucchini into generous ½-inch pieces. Smaller pieces may become too soft while the rice finishes cooking.

  The salt needed will depend on the seasoning in your marinara and beef stock. Start with the listed amount, then taste and adjust before adding the final cheese topping.

  Watch the skillet closely under the broiler. The cheese can go from lightly browned to burned quickly, and the skillet handle will remain extremely hot after it comes out of the oven.