Sharp cheddar cheeses vary with intensity of flavor. For this recipe we assume a standard grocery store label extra sharp cheddar.
If you are using a specialty sharp cheddar (some of the Irish cheddars are lovely), you may be able to accomplish the same amount of flavor with less cheese than is called for in this recipe.
Some people are much more sensitive to bitter flavors than others. It’s genetic. So if that’s you, I would use only a quarter of a cup or skip the beer entirely, and just add more stock.
Method
1 Sauté onions and celery: Melt butter on medium heat in a large, thick-bottomed pot. Add the onions and cook until golden, about 10 minutes. Add the celery and cook 5 minutes more.
2 Add the sliced potatoes to the pot. Add the chicken stock, Guinness extra stout, and thyme. Bring to a simmer, lower the heat, partially cover, and simmer until the potatoes are tender and easily fall apart, about 15 to 20 minutes.
3 Purée the soup, adding grated cheddar: When the potatoes are tender, remove the pot from the heat. Pour potato mixture into a bowl and let cool for a few minutes.
Working in batches, ladle the soup into a blender, filling the blender bowl only a third full at a time.
Add a portion of the grated cheddar to the blender bowl as well. (If it takes 3 batches to purée the soup, divide the cheese into 3 portions. )
Holding the lid of the blender down (to keep the hot liquid from erupting out of the blender), pulse until smooth. Return the smooth purée to the soup pot.
4 Stir in the Worcestershire sauce and paprika. Taste for salt and add more if necessary. If the soup is too sour or bitter to your taste, add 1/2 teaspoon of sugar to the soup.
Garnish with chopped chives.
