Pour about 1/2 cup of spaghetti sauce into the bottom of a large, cast-iron Dutch oven with lid. Spread the sauce around evenly.
Place down a layer of three lasagna noodles, and spread about 3/4 cup of spaghetti sauce over them. Lay in the broccoli and sprinkle with 2/3 cup of mozzarella cheese. Repeat this layering of noodles, sauce, vegetables, and cheese using the cauliflower, green peas, and corn.
Cover the corn with the last three remaining lasagna noodles, and spread the remaining spaghetti sauce on top. Sprinkle with the Cheddar cheese.
Place the lid on the Dutch oven, and place 12 hot coals underneath and 12 coals on top. Cook for 75 minutes or until noodles are soft and tender. Remove the coals, and allow to stand for about 10 minutes to firm up a bit before serving.
