To make the crust, place 20 vanilla wafers in a food processor until finely crushed. Slowly, pour the melted butter into the food processor while it is on. Remove, and firmly press on bottom, up sides, and onto lip of a 9-inch pie plate.
Bake at 350° for 10 to 12 minutes or until lightly browned. Remove and cool 30 minutes.
For Pie:
Arrange banana slices evenly over bottom of crust. spread half of hot filling over bananas. Top with 20 vanilla wafers. Spread remaining hot filling over vanilla wafers.
Beat egg whites at high speed with an stand or electric mixer until foamy. Add sugar, 1 teaspoon at a time, beating until stiff peaks form. Spread meringue evenly over hot filling to the edges to seal them.
Bake at 350° for 10 to 15 minutes or until golden brown. Remove from oven, and let cool 1 hour. Chill 4 hours before serving.
For Vanilla Filling:
Whisk together sugar, flour, eggs, egg yolk and milk in a heavy saucepan. Cook over medium-low heat, whisking constantly, 8 to 10 minutes or until it reaches the thickness of chilled pudding. Remove from heat, and whisk in vanilla.
Cook over medium-low heat, whisking constantly, 8 to 10 minutes or until it reaches the thickness of chilled pudding. Remove from heat, and whisk in vanilla.