Prepare and bake 9-inch pie shell; set aside to cool.

In a medium saucepan, add milk and vanilla. If you are using a vanilla bean, scrape well and add to pot, together with empty bean (you’ll remove this later).

In a large saucepan, combine the sugar, flour and salt; If you used a vanilla bean, you may now remove it. Gradually stir in the scalded milk, whisking continuously.

Cook until thickened over medium heat, stirring continuously. Cooking times will vary, depending on your stove top. Once mixture thickens, reduce heat to medium-low and cook for an additional 2 to 3 minutes, stirring every now and then.

Meanwhile, separate your eggs.

In a small bowl, lightly beat the 3 egg yolks; DO NOT ADD to the saucepan yet, you’ll need to temper the egg yolks first! To do so, add the hot mixture a little at a time, stirring continuously (start out by adding a tablespoon at a time) and once you have added enough of the mixture to slowly bring the temperature of your egg yolks up, you may add the yolks to the saucepan.

Continue to cook for one minute longer, stirring continuously. Your mixture should look about the same thickness as this, and should be capable to easily coat the back of a spoon without dripping off.

Remove saucepan from heat and blend in the butter.

Set aside and permit to cool until lukewarm; your mixture will continue to thicken as it cools.

When custard is cooled: slice bananas and layer in pie shell.

Pour custard over bananas.

Refrigerate for 2 to 3 hours, or until custard is set. Top as desired.

* Whole milk is suggested; if you’re using anything less (1-2%) I suggest substituting a portion of it with heavy cream to obtain the mandatory consistency for the custard.