Cauliflower Cheese Soup

1 med. head cauliflower, cut up into small pieces, cooked til tender and drained
1/4 cup butter or margarine
2/3 cup chopped onion
1/2 cup flour
2 can chicken broth
2 cups half & half (fat free)
1/2 tsp. Worcestershire sauce
3/4 tsp. salt
1 cup cheddar cheese, grated

Melt butter, add onion and cook until tender. Blend in flour and cook for 2 minutes. Add chicken broth. Cook, stirring constantly, until it boils. Add half & half, Worcestershire sauce and salt. Add cooked cauliflower and head. Add cheese.