• Cook the ground beef, onion and bell pepper in a dutch oven or large skillet over med heat. Cook and stir until meat is brown with no pink showing
• Add tomatoes with juice, tomato sauce, oregano, and basil and bring to a boil. Add hot water if the sauce is too thick. I always add a whole carrot at this point. (the carrot will remove the acid and after the sauce is done, just remove the carrot)
• Reduce heat and simmer for 15-20 minutes while you are grilling the zucchini slices.
• Prepare the defrosted spinach by draining well. Use paper towels or tea towel to wring all the water out of the spinach. (It will affect your zucchini lasagna if the spinach is too wet)
• Slice the zucchini into thin slices, I used a mandoline but you could use a sharp knife. Season with olive oil to cover each slice and then add freshly ground black pepper and salt. Heat grill or grill pan and grill zucchini until done, turning halfway through.
• In a medium bowl, add the ricotta cheese, egg whites and 1/2 cup of low-fat mozzarella cheese. Blend well

To assemble:

• Spoon 1/3 of the meat sauce in an 8 X 8 baking dish
• Place 1/2 of the zucchini slices on top of the meat sauce, completely covering the sauce.
• Spoon 1/3 of the cheese mixture on top of the zucchini and spread it as best as possible
• Add 1/2 of the spinach and then another 1/3 of the meat sauce spreading into layers
• Place the remaining zucchini, following with the cheese mixture, spinach, and the remaining meat sauce
• Top with the last 1/3 of the cheese mixture and sprinkle with 1/4 cup of additional mozzarella cheese
• Cover and bake in a preheated 325-degree F oven for 45 minutes
• Remove foil and bake for 10-15 minutes. Remove and let sit for 5 minutes before serving.