For the crust:

In a medium bowl, stir together crushed vanilla wafers and butter until blended. Firmly press on bottom and up the sides of a 9-inch pie plate. 

Bake at 350° for 10 to 12 minutes or until lightly browned. Remove to a wire rack, and let cool 30 minutes or until completely cool.

For the pudding: Whisk together sugar, flour, eggs, yolks and milk in a heavy saucepan. Cook over medium-low heat, whisking constantly, 10-12 minutes or until it reaches the thickness of chilled pudding. (Mixture will just begin to bubble and will be thick enough to hold soft peaks when whisk is lifted. It must be thick and slightly bubbly to set up properly!) Remove from heat, and stir in vanilla. 

Transfer to a medium bowl and cover with plastic wrap, making sure to press the plastic directly on top of the custard so it doesn't get a "skin" on it. Refrigerate til completely cool. (Can be made up to a day in advance.)

Whipped Cream: In a medium bowl, whip cream on medium high speed til soft peaks form. Slowly add the sugar and vanilla and continue to beat til thick and stiff. Don't overbeat or you'll have butter!

Assembly: Arrange half of the banana slices evenly over bottom of cooled crust. Spread 1/3 of cooled pudding over bananas, then layer with 20 vanilla wafers. Spread 1/3 more pudding over vanilla wafers, then add the remainder of the banana slices and cover them with the last of the pudding. Spread the whipped cream over the entire pie and decorate with more vanilla wafers if desired. 

The layers from the bottom up should be: vanilla wafer crust, bananas, pudding, vanilla wafers, pudding, bananas, pudding, whipped cream

Refrigerate at least for 4 hours. Overnight is best. Consume within 2 days. 

NOTE: It's best to prepare the pudding in advance to allow it to chill properly. If you prefer this pie be topped with a meringue then there's no need to refrigerate the filling. See the original recipe here. 

Also I used an entire box of vanilla wafers for the pie. If you want to decorate with additional wafers then get a second box to be on the safe side.