1 lb. light brown sugar
1 c. granulated sugar
4 tbsp. flour
1 c. evaporated milk
1/2 tsp. salt
2 heaping tbsp. marshmallow fluff
1 tsp. vanilla
1/2 c. chopped walnuts

Mix first 5 ingredients in saucepan. When they reach a full rolling boil, boil exactly 5 minutes, stirring constantly. Remove from heat; add 1 tablespoon of butter, marshmallow fluff, vanilla and nuts. Beat until creamy. Turn into buttered 8x13 pan.