Ingredients

  • 3 cups chicken stock or low-sodium broth
  • 2 large leeks, white and tender green parts only, halved lengthwise
  • Salt and freshly ground pepper
  • 2 pounds white potatoes, peeled and cut into 2-inch chunks
  • 1 tablespoon unsalted butter, at room temperature
  • 1 cup milk, warmed
  • 1 tablespoon vegetable oil
  • 8 white veal-and-pork sausages such as boudin blanc or bockwurst, halved lengthwise
  • 1 cup heavy cream
  • 2 teaspoons grainy mustard
  • 1 teaspoon Dijon mustard
  • 1 tablespoon chopped parsley

Method

  • In a large skillet, bring the chicken stock to a boil.
  • Add the leeks and a pinch each of salt and pepper.
  • Cover partially and simmer over low heat, carefully turning the leeks once, until tender, about 10 minutes.
  • Using a slotted spoon, transfer the leeks to a plate.
  • Pour the stock into a large glass measuring cup.
  • In a large saucepan, cover the potatoes with water.
  • Add a large pinch of salt and bring to a boil over moderately high heat until tender, about 12 minutes.
  • Pour off the water.
  • Set the saucepan over the hot burner and shake the potatoes for 1 minute to dry them out.
  • Pass the potatoes through a ricer into a medium saucepan.
  • Gently stir in the butter, then stir in the milk.
  • Season the potatoes with salt and pepper and cover.
  • In the large skillet, heat the oil until shimmering.
  • Add the sausages and cook over high heat until lightly browned, about 1 minute per side.
  • Pour in the reserved leek cooking broth, cover and simmer over moderately low heat for 5 minutes.
  • Transfer the sausages to a warmed platter and cover with foil.
  • Boil the broth in the skillet over high heat until reduced to 2 cups, about 3 minutes.
  • Add the cream and boil until reduced by one-third, about 10 minutes.
  • Stir in both mustards and season with salt and pepper.
  • Add the leeks to the sauce and simmer over low heat until heated through.
  • Rewarm the potatoes, still covered, over moderately high heat, stirring once.
  • Spoon the potatoes onto plates and set the sausages and leeks next to them.
  • Spoon the mustard sauce over the leeks and potatoes, sprinkle with the parsley and serve.