Mushroom Sauce

2 Tb. butter 1 slice of carrot 1 slice of onion
Sprig of parsley 1/2 tsp. salt 1/8 tsp. pepper 2 Tb. flour 1 c. meat stock 1/2 c. mushrooms 2 tsp. lemon juice

Put the butter in a frying pan with the carrot, onion, parsley, salt, and pepper, and cook together until brown. Remove the onion, carrot, and parsley.
Stir in the flour, brown it slightly, and then add the meat stock. Cook together until thickened. Just before removing from the fire, add the mushrooms, chopped into fine pieces, and the lemon juice. Allow it to heat thoroughly and then serve.