Cauliflower Soup

1 small head of cauliflower
3/4 cup chopped onion
1/4 cup butter
2 cups half and half
1/2 tsp salt
1/3 cup flour
2 cups chicken broth
1/2 tsp Worcestershire sauce
2 cups cheddar cheese
Cook cauliflower until tender, reserve 1 cup of the cauliflower water for reserve.
Melt butter, add onions. Blend flour and broth. Add 1 cup reserve water. Add sauce and salt and half and half. Add cheese when melted add cauliflower.