Heat olive oil in large skillet over medium-high heat.
Add chopped onion and cook for 3 minutes.
Add minced garlic and cook for 1 minute more.
Add ground beef to the skillet immediately.
Cook beef until browned, breaking it into small pieces.
Drain excess fat from the pan carefully.
Add diced zucchini to the beef mixture now.
Season with oregano, basil, paprika, salt, and pepper.
Cook for 5 minutes, stirring occasionally throughout.
Add diced tomatoes with their juice to skillet.
Simmer for 8-10 minutes until zucchini is tender.
Sprinkle cheese on top if using it.
Garnish with fresh parsley before serving immediately.