Place the milk and sugar in the work bowl. Process at speed 4, 100 C until temperature is reached.
Insert butterfly. Gradually add the flour, sugar, and salt. Process at speed 3 until thickened. Continue to process for 2 more minutes.
Beat the egg yolks in a small bowl. Add a little of the milk mixture to the eggs while continuing to whisk in order to temper the eggs. Continue to add the milk mixture until about a cup is added. Continue to mix throughout.
Add the egg mixture to the remaining milk mixture. Process for another minute.
Remove from processor and stir in butter and vanilla. Allow to sit until lukewarm.
Slice bananas and place on the bottom of the pie shell. NOTE, This can be a single shell or multiple. If Using 8 shells as shown above, each will be approximately 90 grams. Pour the pudding over the bananas
Top with Swiss Meringue if desired.