Leek and Potato Puree
6 portions

6 large leeks
2 pounds red-skinned potatoes
12 tablespoons (1 1/2 sticks) sweet butter
2 garlic cloves, minced
1/2 cup heavy cream
salt and freshly ground pepper, to taste

1. Trim roots and most, but not all, of the green leaves from leeks, leaving each leek about 7 inches long. Split down to but not through the base and wash thoroughly.

2. Bring 3 quarts salted water to a boil in a pot, add leeks, and cook until tender, about 15 minutes. Drain and chop.

3. Meanwhile, peel the potatoes. Cover them with cold water in another pot. Add salt and bring to a boil. Reduce heat and cook until potatoes are very tender, 20 to 40 minutes, depending on the size. Drain and reserve.

4. Melt 3 tablespoons of the butter in a skillet. Add the garlic and cook over low heat until lightly colored, about 15 minutes. Add leeks and an additional 3 tablespoons butter and continue to cook, stirring occasionally, for 15 minutes.

5. Transfer leeks-and-butter mixture to the bowl of a food processor fitted with a steel blade, and purée until smooth.

6. Mash the potatoes, adding heavy cream as needed. Stir in the leek purée and remaining 6 tablespoons butter; season with salt and pepper. Reheat gently until steaming. Serve immediately.