Wash the peas, soak for 12 hours (unless you use quick cooking peas) and boil gently in the water they were soaked in for at least two hours. Cook in this liquid the trotter and the ear and the bacon for one hour. Add the sliced potatoes, salt, diced celeriac, cut up leeks and celery leaves and cook until everything is done and the soup is smooth and thick. Add the Frankfurters for the last 10 minutes. The longer the soup simmers, the better the taste. 3 hours is the usual time in Holland. The soup gets so thick when it cools that it can be cut next day. The next day the soup tastes even better, when reheated. That is why it is made in such big quantities.