Mashed Sweet Potato with Melted Leeks

rim roots and wilted leaves from leeks. Cut in half lengthwise. Slice each half crosswise into 1/4-inch slices. Place in a colander and rinse well to remove any grit. Drain and dry leeks.

In a 5- to 6-quart Dutch oven, cook sweet potatoes with 1 teaspoon of salt in enough boiling water to cover for about 10 to 12 minutes until potatoes are just tender. Drain; return to pot.

Meanwhile, heat butter in a large skillet over medium-high heat until melted and beginning to bubble. Add leeks, reduce heat to medium and cook for about 6 minutes, or until leeks are just tender, stirring occasionally. Add stock, lemon zest and juice, thyme, pepper and remaining 1/2 teaspoon salt. Cook and stir for 3 minutes.

Add about two-thirds of leek mixture to potatoes and mash with a potato masher until desired consistency. Transfer to a serving bowl and top with remaining leek mixture.