I call this vichyssoise country
because when you make it in the blender (even multiple passes), you still get a few tiny lumps. Also I use black pepper, not white, so it is not perfect in appearance. This recipe is based on an old edition of my bible, The Joy of Cooking.
Sauté a few sliced leeks (white part) and a sliced onion in a few tbsp of butter. When soft, add four peeled, sliced potatoes and four cups of dilute chicken broth. Simmer until tender. Blend until smooth; I usually pass the whole thing through the blender multiple times; the traditional thing is to force it through a sieve. You want it to be as smooth as possible. Salt and pepper the blended soup until it tastes good.
Chill. Add a cup of cream and wisk till perfectly blended. Serve cold (even ice cold) with chopped chives or green onions.
Vichyssoise is easy to make, but I can't quite figure out how to make it well. Maybe PMC can weigh in on this. The best I have ever had is in Le Café de Paris by the Casino in Monte Carlo. It was rich in taste but also very light in consistency. Perhaps the traditional method of forcing the soup through a fine sieve is better than blending it. That sounds dangerously like rocket science.