Friends, this soup is SO GOOD. it’s my go-to recipe when it’s cold and grey and I need comfort food that isn’t too fattening. As a bonus, it’s pretty much goof-proof once you know how easy it is to properly prepare the leeks. I like to double wash them, just to make sure no grit gets into this delicious soup.
1 pound leeks, cleaned and dark green sections removed, approximately 4 to 5 medium
8 tablespoons unsalted butter, separated
Heavy pinch kosher salt, plus additional for seasoning
14 ounces, approximately 3 small, Yukon gold potatoes, peeled and diced small
1 quart vegetable broth (or 4 cups water + 4 teaspoons “Better Than Bullion Not-Chicken”)
1 cup heavy cream
1 cup buttermilk
3 tablespoons all purpose flour (I use King Arthur unbleached)
3 tablespoons nutritional yeast
1/2 teaspoon white pepper
1 tablespoon snipped chives
To prepare the leeks –
Cut off the dark green leafy parts, leaving only white or light green behind.
Cut off the “beard” at the bottom.
Slice the leeks in half lengthwise.
Holding the two halls together, chop the leeks into small pieces.
Submerge the sliced leeks in a bowl of cool water and swish them around thoroughly.
Let the leeks sit in the water for five minutes – this will allow any dirt or sand to sink to the bottom.
Using your hands, gently scoop the leeks from the bowl and into a colander.
Using your sink sprayer, rinse the leeks thoroughly, shaking the colander to make sure you get them all.
Set them aside to drain, or if you’re in a hurry dump them on a clean kitchen towel and press to dry. You can also use a salad spinner if the pieces aren’t so small that they’ll go through the slats.
In a 6-quart saucepan over medium heat, melt 3 tablespoons of the butter. Add the leeks and a heavy pinch of salt and sweat for 5 minutes. Decrease the heat to medium-low and cook until the leeks are tender, approximately 25 minutes, stirring occasionally.
Add the potatoes and the vegetable broth, increase the heat to medium-high, and bring to a boil. Reduce the heat to low, cover, and gently simmer until the potatoes are soft, approximately 45 minutes.
Purée the mixture with an immersion blender until smooth. Stir in the heavy cream, buttermilk, and white pepper. (Note – if you don’t have buttermilk, simply stir 1 tablespoon lemon juice into 1 cup of milk and allow it to sit for five minutes).
In a separate small saucepan, melt the remaining 4 tablespoons of butter. Whisk in the flour and nutritional yeast, making a roux. Maintain just enough heat to make the roux bubble, but not burn! Cook, whisking constantly, for four minutes.
Whisk the finished roux into the puréed potato and leek mixture. The soup will thicken slightly as you do.
Taste and adjust seasoning if desired. Sprinkle with chives and serve immediately, or chill and serve cold.