CROCK POT FRENCH ONION SOUP

1 qt. beef bouillon or stock
2 to 3 c. sliced onion
1/4 c. butter
1 tsp. Worcestershire sauce
2 tbsp. flour
1/4 c. dry vermouth or white wine
(optional)
1 1/2 tsp. salt

Pour bouillon in crock pot. Cover and set on high. Cook onions slow in large skillet in butter. Cover and let cook 15 minutes. Add remaining ingredients to onions. Stir well and add to stock in crock pot. Cover and cook on low 6 to 8 hours or 3 hours on high.