Stew onion on water at low heat to prevent burning. Add various vegetables, celery, parsnips, carrots and cook a little longer. Cut mushrooms into cubes and add to the vegetables to be stewed together. When almost cooked, add fresh pepper, zucchini and tomatoes into cubes or milled. Stew till cooked, add herbal spices, a spoon of olive oil (if fasting, without oil) and salt.