4 tbsp. butter
1 bunch leeks, white part only
1 lg. Spanish potatoes
2 lbs. purple potatoes
4 cloves garlic
1 1/2 qts. chicken stock
1 c. heavy cream
Salt and pepper

Slice the leeks and onion and mince the garlic. Saute these in the butter for 8 to 10 minutes, until soft. Dice the potatoes and add them (unpeeled) to the vegetables. Saute another 5 minutes. Add the stock and simmer until the potatoes are soft, about 20 to 30 minutes. Remove from heat and let cool 15 to 20 minutes. Puree the mixture in a blender or food processor until smooth. Return puree to pan and add cream; heat on low and season to taste.