Butterscotch Pie

Directions

1. 1
   In double boiler, combine sugars with flour and add hot milk gradually.
2. 2
   Stir constantly to make smooth.
3. 3
   Add salt and cook for 15 minutes, stirring occasionally until thick.
4. 4
   Pour part of mixture slowly into egg yolks, stirring constantly.
5. 5
   Pour back into double boiler; mix well and cook 3 minutes.
6. 6
   Stir and add butter.
7. 7
   Cool and add vanilla.
8. 8
   Pour into pastry shell.