Best Soup Recipe - Cheddar-Ale

Finding that I had three completely different recipes for Cheddar-Ale soup and none of them were vegetarian I experimented with the best elements of them all and made a vegetarian version that has to be the best soup I've ever had. Dipping vegetables and bread into it like fondue was also a fun way to use the leftovers. Here is my recipe:

1/2 stick of margarine or butter
1/2 of 1 large yellow or white onion, diced
2 celery stalks, diced
3 carrots diced
1/3 cup all-purpose flour
1 3/4 cups milk (I used 1%)
1 3/4 vegetable stock
12 fl. oz. of ale (approx. 1 bottle)
1 tsp. dry mustard
1 1/4 sharp cheddar cheese, grated

Put large pan over medium-low heat on stove. Melt butter and then add onion, celery, and carrots. Let cook (and stir occasionally) until softened, about 10 minutes. Then stir in flour and let cook for approx. 3 minutes. Increase heat to med-high and stir in milk and vegetable stock. Simmer until thickened (took me around 5 minutes) and stir throughout. Put this mixture into blender and puree until smooth.

Put puree into stockpot and set over medium heat. Add ale and mustard then let simmer for 5 minutes. Stir grated cheese into mixture 1/2 cup at a time slowly. Serves 4-6
Enjoy!!