Black Walnut Chess Pie

1 7 1/2" Pastry Shell -- unbaked

1/2 c Butter -- softened

1 c Sugar

3 tb Flour

1/8 ts Salt

3 Egg Yolks

2/3 c Evaporated Milk

1 t Vanilla

1/2 c Chopped Walnuts

Prepare pastry shell; chill. Beat butter and sugar in a medium sized bowl until well-mixed. Add flour, salt, egg yolks, and evaporated milk. Beat until well mixed. Stir in vanilla and walnuts. Pour mixture into unbaked shell. Bake on lower rack of oven at 375 Degrees for 45 minutes or until center is set but still soft. Cool

thoroughly.