Preparation:
Peel and quarter the potatoes. Prepare the leeks by removing the green portions, reserving for another use if desired. Cut down the center lengthwise and wash thoroughly. Chop the white portions finely and sauté lightly with the chopped shallots in half the butter for 5-7 minutes. Add 1 quart of water or chicken stock, 1/2 teaspoon of salt, celery, the quartered potatoes, and simmer 20-25 minutes. Remove potatoes and leeks to a small bowl, reserving using a potato masher, mash to a puree in return the puree to the cooking water. Stir in the milk, cream, and remaining butter, reheating one minute if needed. Season to taste with salt and pepper.

Garnish with parsley and croutons.