Add rice to 300 ml salt water and let it swell at low heat for about 20 minutes. Clean and wash the zucchini. Cut off about 1/3 of the length of each zucchini and dice finely. Hollow out the remaining zucchini with a teaspoon. Clean, wash and pat mushrooms dry.
Chop the mushrooms. Wash, clean, quarter and seed the tomatoes. Cut the flesh into cubes. Peel and dice onion and garlic. Steam onion, garlic, zucchini cubes and mushrooms in hot oil for about 3 minutes. Wash the chives, dab dry and cut into small rolls. Add tomato cubes, rice and chives to the vegetables. Grate cheese and fold in the crème fraîche. Season to taste with salt and pepper.
Wash the chives, dab dry and cut into small rolls. Add tomato cubes, rice and chives to the vegetables. Grate cheese and fold in the crème fraîche. Season to taste with salt and pepper. Fill the vegetable rice into the hollowed out zucchini. Put them into an ovenproof dish, pour on the broth and bake in a preheated oven (electric range: 200 °C/ gas: level 3) for about 20 minutes