Freely adapted from a recipe by Alton Brown on the Food Network site:

2 T. butter or margarine
1 cup diced onion
1 cup diced carrot (I actually used some pre-shredded carrot from the produce section)
1 cup diced celery
1/2 t. salt
3 T. all-purpose flour
1 quart chicken broth (one box)
2-3 garlic cloves, minced
1 t. red pepper flake (or less to taste)
1/2 t. black pepper
1 cup whipping cream
10 ounces shredded cheddar cheese
2 t. Worcestershire sauce

Melt butter in large heavy-bottomed soup pot or electric kettle over medium heat. Add onion, carrot, celery, and salt. Sweat for 5 to 10 minutes. Sprinkle the flour over the vegetables and cook, stirring constantly, for 2 to 3 minutes.

Gradually add the chicken stock and bring to a boil, stirring constantly. Reduce heat to low and add the garlic, red pepper and black pepper. Cover and simmer for 30 minutes or until vegetables are soft.

Turn off the heat and puree with an immersion (stick) blender until the vegetables have been completely pulverized. If you don’t have a stick blender, you should, but in the meantime you could let the soup cool and carefully puree it in batches in a regular blender. Beware of the effect that makes hot liquids explode in a regular blender!

After the soup has been pureed, add the cream and warm the soup slightly if necessary. Add the cheese, a little at a time, stirring each batch until melted before adding the next batch. Add the Worcestershire sauce, check for seasoning, and serve.