Cut the tops off the tomatoes and use a spoon to remove the insides. Sprinkle with salt and turn them upside down to drain any excess liquid.
For the filling, sauté the finely chopped onion in the oil. Once the onion is softened, add the minced meat along with the grated parsnip, carrot, and celery. Season with rosemary and cook until the vegetables are tender.
Fill the tomatoes with the prepared mixture. Beat the egg with the parsley and Cremio cooking cream, and pour it over the stuffed tomatoes. Bake the tomatoes in a preheated oven at 220°C.