01 - Set the oven to 400°F (200°C) to heat while preparing the ingredients.
02 - Cut zucchini in half lengthwise and scoop out the center flesh, leaving a ½ inch shell. Finely chop the scooped flesh and set aside.
03 - Arrange zucchini halves cut-side up in a baking dish, drizzle with 1 tablespoon olive oil, and season lightly with salt and black pepper.
04 - Heat remaining 1 tablespoon olive oil in a skillet over medium heat. Cook onion until softened, about 3 minutes, then add garlic and cook for 30 seconds more.
05 - Add ground beef to the skillet, breaking it apart and cooking until browned, approximately 5 to 6 minutes. Drain excess fat if necessary.
06 - Stir in chopped zucchini flesh, diced tomato, tomato paste, oregano, basil, paprika, salt, and pepper. Simmer for 5 minutes until mixture thickens and vegetables soften.
07 - Spoon the beef mixture evenly into each zucchini half, then sprinkle shredded mozzarella cheese over the top.
08 - Cover the dish with aluminum foil and bake for 20 minutes to meld flavors and soften zucchini.
09 - Remove foil and bake another 5 to 10 minutes until the cheese is golden and bubbling.
10 - Optionally sprinkle with chopped fresh parsley before serving.