Author Notes: When my husband or I make potato soup, our default is Julia Child's Potage Parmentier, but sometimes I want a soup with a little more pizzaz. Cheddar, dill and Dijon mustard provide just that in this hearty soup, which comes together quickly enough for a weeknight dinner, and tastes even better the next day. —lastnightsdinner
- 1/4 cup unsalted butter
- 2 cups sliced leeks (white and pale green parts, only)
- kosher or sea salt
- 1 tablespoon unbleached, all-purpose flour
- 1 quart chicken or vegetable stock, preferably homemade
- 4 cups peeled, cubed waxy potatoes
- 2 tablespoons sharp Dijon mustard
- 1 cup firmly packed grated sharp farmhouse Cheddar cheese
- 1/4 cup chopped fresh dill, plus additional for garnish
- Melt the butter in a heavy bottomed soup pot.
- Add the leeks and a generous pinch of salt, and cook over medium heat until soft.
- Sprinkle the flour over the leeks and stir until coated. Cook for a few minutes, then add the stock, potatoes, and mustard, stirring until the mustard dissolves into the soup.
- Bring to a boil, then reduce the heat to low, cover, and cook until the potatoes are very tender when pierced with a fork.
- Turn off the heat and puree the soup with an immersion blender.
- Turn the heat back on low and add the cheese, stirring well until it melts into the soup.
- Taste and adjust seasoning. Add the dill just before serving, stirring it through. Sprinkle additional dill on top of each serving.