Slice approximately 4-5 bananas and place in pie shell. Layer in a circular form, starting with the outside and working into the inside.
In heavy bottomed saucepan, combine sugar, flour, and salt. Gradually stir in milk. Cook and stir over medium heat until bubbly. Cook and stir for 2 min. Remove from heat.
Stir in a small amount of mixture into egg yolks; immediately return to hot mixture; cook approx. 2 minutes or until thickened, stirring constantly (be careful of scorching). Remove from heat. Add butter and vanilla. Pour filling on top of bananas in pie shell.
Refrigerate for 3-4 hours until thick and firm. Then add whipped cream or Cool Whip. Keep refrigerated until ready to eat.
Recipe by The Gingham Apron at https://www.theginghamapron.com/banana-cream-pie/