Cream Pie- Coconut or Banana

I am a fan of my mom's cream pies. I double this recipe for the filling of one pie.

1 1/2 cup milk
1/4 cup sugar
1/4 tsp. salt
3 tbsp flour or cornstarch
1 egg yolk
1 tbsp butter
1/2 tsp. vanilla
coconut
coconut oil
or bananas

Scald 1 cup milk. Slowly add while scaldens, sugar, salt, flour and mix. Stir constantly til thickened. Beat egg yolk and combine 2 tbsp. mixture to the yolk. Slowly add back mixture and cook 2 more minutes. Take off heat and add butter, vanilla and coconut as well as oil or bananas. Cool and add to pie crust.