Wisconsin Beer Cheese Soup (Chef Tried & True)

Name: Wisconsin Beer Cheese Soup (Chef Tried & True)
Prep time: 10 min
Cook time: 20 min
Total time: 30 min
Cuisine: American
Ingredients: 1/4 cup butter; 1 yellow onion, large, diced; 2 celery stalks, diced; 2 carrots, medium, diced; 1/2 red or orange bell pepper, diced; 2 cloves garlic, minced; 1 bay leaf; 1/3 cup flour; 2 1/2 cups chicken broth (or vegetable as substitute); 1 cup heavy cream; 12 oz beer, well-balanced or predominantly malty; 1 tsp salt (or to taste); 1/2 tsp pepper; 1 tsp dry mustard, (ready powdered or grind whole mustard seed); 1 tbsp Worcestershire sauce; 1/2 tsp cayenne or red pepper flakes, optional; 3 cups shredded Cheddar cheese, (white cheddar works too); 3 stalks green onion, green part only, chopped, for garnish; bread croutons , optional, for garnish