Peel the vegetable onions and cook in boiling salted water for about 20 minutes
Peel and chop the onion and garlic. Heat the fat, fry the onion and garlic for about 3 minutes. Add the spinach and stew at low heat in a closed pot for about 10 minutes. Season to taste with salt, pepper and chilli powder
Remove the onions from the water and hollow them out. Chop the inside of the onion. Heat the oil in a pan and fry the minced onion for about 5 minutes, turning it over. Season with salt and pepper. After about 3 minutes add half of the onion interior. Lightly squeeze out the spinach and fold into the mince. Coarsely grate cheese
Season hollowed onions inside and outside with salt and pepper. Spread the spinach mince pan into the onions. Put the rest of the chopped onions and broth in an ovenproof dish. Place the onions on top and sprinkle with cheese. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 45 minutes