In a large pot cook ground beef and onion over medium heat, until beef is browned and onion is tender.
Add garlic and green pepper and cook for 2-3 minutes more until tender.
Use your hands to break up the whole tomatoes as you add them to the beef mixture. Stir in the tomato juices, Italian seasoning and chili flakes (if using).
Bring to a boil, reduce to low heat, and simmer for 30 minutes.
Meanwhile, wash zucchini and remove the ends. Use a spiralizer or a vegetable peeler to create "noodles".
Heat olive oil in a pan over medium heat. Add zucchini and cook for 2-4 minutes or until slightly softened (do not overcook). Season to taste with salt and pepper.
To serve, top zucchini with pasta sauce and a sprinkle of parmesan cheese.
Notes
If you don't own a spiralizer, simply cut zucchini into thin ¼” slices, lay them flat, and slice into thin “noodles.”
Use up to a tablespoon of olive oil to cook them, ensuring they remain tender-crisp, like al dente pasta.
Serve zucchini spaghetti immediately after pan-frying for the best results.