Place a layer of Nilla Wafers in the bottom of a medium sized mixing bowl. Slice a banana over the top. Repeat two more times with another layer of wafers and remaining bananas.
In sauce pot (or double boiler) on medium low heat, add all ingredients except for vanilla. Stir well with wire whisk. Allow to cook, stirring constantly to prevent scorching, until thickened - about fifteen minutes.
Add in vanilla and stir. Immediately pour over wafers and bananas.
Whip egg whites until foamy. Add sugar. Continue beating on high speed until soft peaks form. Pour onto top of pudding and spread to edges to seal well. Bake at 325 for ten minutes or until top is golden.