3/4 cup brown sugar, firmly packed
5 tablespoons flour
1/2 teaspoon salt
2 cups milk
2 egg yolks, slightly beaten
2 tablespoons butter
1/2 teaspoon vanilla extract
Prepared 9-inch Pie Crust
In the top pot of a double boiler, start butterscotch by combining brown sugar, flour, and salt. Add the milk slowly, mixing well. Cook over rapidly boiling water until well thickened, stirring constantly. Cook for about 10 minutes longer, stirring occasionally.
Stir a small amount of the hot milk mixture into the slightly beaten egg yolks, then pour the tempered egg yolks back into the butterscotch while beating vigorously. Cook a minute longer. Remove the pot from the heat and add butter and vanilla. Stir to combine. Cool a bit, then pour into baked 9-inch pie shell. Refrigerate at least one hour prior to slicing and serving.
Makes 6 8 servings.