Like onions, leeks develop a rich, savory flavor when cooked slowly. And when cooked this way, they make an excellent addition to a creamy mound of mashed potatoes.
Rather than caramelize the leeks, which requires a bit more hands on cooking, we decided to melt them. It's actually a braise, but the result is meltingly good. And braising requires only an occasional stir. The leeks are thinly sliced, then slowly simmered in broth or stock until extremely tender, then the whole mixture is stirred into the potatoes.
The easiest way to clean leeks is to cut them up first. Trim off the ends, cut them in half lengthwise, then thinly slice them. Place the slices in a large bowl of cool water and toss well, separating the layers, to rinse away any dirt. Allow the dirt to fall to the bottom of the bowl, then use a slotted spoon to scoop out the floating leeks.
3 pounds Yukon gold potatoes, peeled and cut into chunks
3 tablespoons unsalted butter
3 cups thinly sliced and cleaned leeks
1/2 cup chicken stock or broth
1/2 cup half-and-half
3 tablespoons chopped fresh chives
Place the potatoes in a large stockpot. Add enough water to cover by 1 inch. Set over high heat and bring to a boil. Cook until tender, about 20 minutes.
While the potatoes cook, prepare the leeks. In a large skillet over medium-high heat, melt the butter. Add the leeks and broth and cover. Bring to a simmer, then reduce heat to maintain the temperature and cook, stirring occasionally, until the leeks are extremely tender, about 30 minutes.
When the potatoes are cooked, drain and return to the pot. Add the half-and-half, then mash until smooth. Season with salt, then stir in the melted leeks - along with any liquid in the pan - and the chives.