Blanch the parsley leaves in boiling, salted water for 30 seconds, rinse in cold water, drain and dry with kitchen paper. Heat the broth, puree with the parsley and strain through a fine sieve.
Boil the peeled potatoes in salted water and mash them thoroughly to the pulp. Stir in enough parsley stock until the puree has a creamy consistency. If it is still too firm, stir in some milk as well. Add butter to the puree and let it melt. Then stir well and season to taste with pepper, salt and nutmeg.
This is a delicious side dish with a nice contrast to dishes with reddish vegetables.