Ingredients:
4 tablespoonsunsalted butter
3 pounds(about 20 stalks) celery, chopped
2 medium potatoes, peeled and diced
1/2 teaspoonkosher salt, plus more to taste
5 cupschicken stock
1/2 cuppesto
Directions:
In a large Dutch oven or heavy-bottomed soup pot, add the butter.
Cook the butter over medium-high heat, swirling the pan occasionally, until the butter begins to brown. First it will foam up, then the foam will subside and the solids at the bottom will begin to take on color. Watch for flecks of amber that begin to darken; this will take about 5 minutes. Stop just before the butter turns deep golden-brown—you want it a little more pale than usual, since you’re going to carry on cooking.
Turn the heat down to medium, add the celery and potato, and season with salt. Cook, stirring occasionally, for about 8 minutes or until the celery begins to soften.
Add the chicken stock; simmer for about 20 minutes.
Use an immersion blender to blend the soup to a creamy texture. (You can also do this in a blender—just be careful transferring the hot liquids, and do it in batches.) Taste the soup and add salt as needed.
Divide between bowls and swirl a generous spoonful of pesto into each bowl. Serve warm.