Slice bananas and dip them into lemon juice, pat dry, set aside.
In a saucepan, over low heat, combine the granulated sugar, cornstarch, salt and milk. Cook over low heat, stirring constantly, until the mixture is bubbly. Keep stirring and cook for several more minutes, until mixture thickens, and then remove from the burner.
Allow the pudding to cool slightly basically until you can put a finger into the pudding but not burn yourself.
Stir the beaten egg yolks into the slightly cooled mixture put the pot back on low and cook for two minutes, continuously stirring. Remove the mixture from the stove, and add butter and vanilla. Stir until the whole thing has a very smooth consistency.
Put in a container and place saran wrap over the surface of the pudding (this avoids getting a skin) and cool for about 2 hours in the refrigerator.
When pudding is ready, place a layer of sliced bananas into your pie shell. Top with the pudding. Add another layer of bananas. Top with whipped cream.
Place sliced bananas on top as desired for garnish. Chill for 1 hour. Enjoy!