Preparation: Blanch lotus seeds, remove reddish brown tip. Wash and soak mushrooms in warm water until soft, about 30 minutes; remove stems; slice in thin matchsticks. Before slicing celery, scrap off stringy back of stalk; slice julienne lengthwise in 3 cm sections. Slice chicken breast and Smithfield ham (or other pungent pressed ham) in 3 cm strips. Soup: Heat stock in 3 litre pan or sandy pot. Add ginger, sherry, sugar and salt. Bring to gentle boil, then add lotus seeds, chicken and mushrooms. Simmer soup for 30 minutes. Add celery and ham. Simmer for another 15 minutes. Mix lotus root powder with a little hot stock, then stir into soup. Transfer to heated serving bowl, or serve in sandy pot. Garnish with Chinese parsley. NOTE: Lotus seeds require about 30 minutes in simmering water to soften. Check them before adding ham and celery; simmer longer if necessary.