Cheddar Soup

Again another recipe from Cook's Illustrated. I changed the recipe only slightly by using potatoes in the recipe. I added one potato chopped. However I also think this recipe needs a very sharp cheese or maybe a combination of some other cheeses. I'm still thinking about what type of cheese to use next time. I also added some green onion to the top of the soup right before serving.

3 tablespoons unsalted butter
1 medium onion , minced (about 1 cup)
1 medium carrot , minced (about 1/3 cup)
1 small rib celery , minced (about 1/4 cup)
1 medium clove garlic, minced
2 tablespoons unbleached all-purpose flour
2 1/2 cups low-sodium chicken broth
2 1/2 cups half-and-half
1 bay leaf
pinch cayenne pepper
3 tablespoons dry sherry
12 ounces sharp cheddar cheese , shredded (about 3 cups)
1 tablespoon minced fresh thyme leaves
Table salt and ground black pepper

1. Heat butter in large heavy-bottomed Dutch oven over medium heat until foaming; add onion and cook, stirring occasionally, until softened, about 4 minutes. Add carrot, celery, and garlic; cook until garlic is fragrant, about 1 minute. Add flour and cook, stirring to coat vegetables, until mixture begins to brown on bottom of pot, about 2 minutes. Gradually whisk in chicken broth and half-and-half and add bay leaf. Increase heat to medium-high and bring to boil; reduce heat to medium-low and simmer until vegetables soften, about 10 minutes.
2. Off heat, add cayenne and sherry; cool soup for 1 minute. Slowly whisk in cheese and thyme; season with salt and pepper and serve immediately.