1 teaspoon lemon juice
1/2 cup water
1/4 cup distilled white vinegar
1/2 teaspoon potato flour
1 (24 fluid ounce) can condensed cream of mushroom soup
6 cups chicken broth
3 tablespoons Worcestershire sauce
1/2 tablespoon salt
1 1/2 tablespoons dry mustard
1 pinch black pepper
salt and vinegar to taste
To saute the lemon juice in a large skillet over medium heat, add water and mix together. Stir in the lemon juice, vinegar and potato flour. Cook over medium-low heat until thick, about 3 minutes. Stir in the chicken broth and Worcestershire sauce. Reduce heat to medium and simmer for 20 minutes. Discard any accumulated sherry and reserve 2 cups of liquid.
Add the remaining liquid from reserved liquid. Stir to combine and heat through. Whisk in the reserved soup and 3 tablespoons Worcestershire sauce and salt and vinegar. Simmer but do not boil.