Soak the bun in some water. Wash the zucchini, and cut zucchini in lengthwise pieces. Remove seeds and with a spoon scoop out ‘flesh’.
Peel onion, and, together with zucchini flesh, cut into small cubes. Wash and dry parsley and chop finely.
In a bowl, mix the ground beef with onion, parsley, zucchini flesh, egg, mustard and spices. Squeeze out the bun and add to the ground beef mixture, and mix into a ‘dough’. Fill the zucchini halves with the filling.
Finely chop garlic and tomatoes, then add tomato juice, garlic, oregano, salt and pepper. Pour this tomato sauce into a shallow baking dish and place the zucchini on top. Sprinkle with cheese.
Do not pre-heat oven. Put into cold oven and then bake at 200 C (400 F) approx. 1 hour.
Serve with baguette and enjoy.