Ingredients
8 tablespoons unsalted butter
2 leeks, trimmed of dark green parts, rinsed well, and finely diced
½ cup vegetable stock
salt and freshly ground black pepper to taste
2 pounds Idaho potatoes
½ cup hot milk
1 cup freshly grated Parmesan cheese
Preparation
In a wide saucepan over very low heat, melt 1 tablespoon of the butter. Add the leeks and braise them, covered, until they are very soft, about 30 minutes; add some of the vegetable stock if they stick to the bottom of the pan. Season with salt and pepper.
Bring a pot of lightly salted water to a boil. Boil the potatoes until they are fork tender, about 12 to 15 minutes, then drain and peel them. Pass the potatoes through a ricer or a food mill, and then put them back into the pot (now dry) on a very low flame. Add the rest of the butter, the milk, and the Parmesan, and beat vigorously with a wooden spoon to blend. Season with salt and pepper, then stir in the braised leeks.
