Wash and peel the asparagus and cut off the woody ends. Wrap the asparagus in a damp tea towel and chill. Boil the asparagus peel, lemon slices and 1 teaspoon of sugar in plenty of boiling salted water for about 20 minutes.
In the meantime, peel the potatoes and cook them in plenty of salted water for about 20 minutes. Lift asparagus shells out of the water with a ladle. Add asparagus to the cooking water and cook for 15-20 minutes. Drain potatoes and toss in butter.
Serve asparagus, potatoes and ham together. Sauce Hollandaise tastes good with it.