1. In a pot, Stir dry ingredients together.
2. Make a well in the center and add egg yolks.
3. Mix well to get the lumps out.
4. Add enough of the milk to get the batter smooth.
5. Add rest of the milk and mix well.
6. Cover over medium heat until very thick.
7. Remove from heat.
8. Add vanilla and butter and mix well.
9. If you don't get the filling very thick, the butter will make it to thin.
10. Pour into 2 cooked pie shells.