Chicken A La King

Ooooh this brings back memories! I would love it when my Mom would fix this for dinner.

1 can mushrooms (discard juice)
1/2 cup chopped green pepper
1/2 cup chopped onion
1/2 cup flour
1 teaspoon salt
1/4 teaspoon pepper
1 1/2 teaspoon chicken bullion
1 1/2 cup milk
1 1/4 cup hot water
2 cups chicken (cooked and cubed)
1 tablespoon lemon juice

Cook mushrooms, green peppers and onion in margarine until tender. On low heat blend in flour, salt and pepper. Cook over low hear stirring until bubbly. Add bullion, milk, water, lemon juice, and chicken. Cook until all is heated through. Serve over rice.