Place broccoli in bottom of 3 qt dish. Place chicken on top.
In saucepan, melt butter. Add flour; cook until thick. Add chicken broth, cream, worcestershire, cheese, mustard, onion and sherry.
Stir until cheese melts. Pour over broccoli and chicken. Freeze.
To Freeze: Freeze in dishes that can go into the oven.
To Reheat: Defrost overnight, bake at 400 for 25 - 30 minutes. Before serving, dash with sherry.