Kremithosoupa is a traditional Greek soup made with onions, garlic, and other vegetables. It is typically served with bread and feta cheese.
Peel, wash and cube the potatoes. Pare and slice the onions. Place these two items into a stock pot and add the tomato sauce, fill with enough water (or broth) to cover them. Add the salt and pepper to taste and boil at moderate temperature for 30 minutes.