I was told this is a Canadian Soup. 'Sounds like what you are looking for (it is wonderful):

2 tb butter
1/4 c onion, finely chopped
1/4 c carrot, finely chopped
1/4 c celery, finely chopped
2 tb flour
1/4 ts dry mustard
pinch nutmeg
pinch pepper
3 c chicken stock
1 1/2 c light cream
1 c milk or beer
1 1/2 c cheddar cheese, shredded
dash Worcestershire sauce
salt as desired

In a heavy saucepan, melt butter, cook onion, carrot, and celery for about
5 minutes or until tender; do not brown. Stir in flour, mustard, nutmeg
and pepper; cook for 2 to 3 minutes.

Stir in chicken stock; simmer for about 20 minutes or until vegetables are
tender. If desired, puree until smooth in blender or food processor.

Add cream and milk or beer and bring almost to a boil. Add cheese; heat
until just melted, stirring constantly. Add Worcestershire and a little salt.