In large glass bowl, make layers of vanilla wafers & bananas. Set aside.
Combine cornstarch, sugar, & salt in pan- wisk in the milk. Cook until hot or beginning to bubble.
Beat egg yolks, stir in small amount of hot milk mixture. Add yolk mixture back to milk mixture.
Cook custard until it thickens, stir constantly. Remove from heat once it coats the back of a spoon.
Stir in butter & vanilla.
Allow custard to cool about 15 minutes.
Pour over cookies & bananas.
Allow about an hour for pudding to set. If you prefer cold pudding, allow pudding to set in refrigerator.
***** This is sooooooooooooo good! My Daddy made the BEST banana pudding!!! ******