Whisk together the 4 cups of sugar and the flour in a large, heavy bottom stock pot (making sure there are no lumps). Whisk in the milk and place on medium heat. Separate the eggs, reserving the egg whites to use in the meringue. Use about 2 cups of the milk mixture to stir into the 12 egg yolks (to temper the eggs before adding them to the hot milk mixture). Once the egg yolks are tempered, mix with the milk mixture. Stir constantly, over medium heat, until thickened. Once you have the right consistency, remove from heat and add the vanilla extract. Layer pudding with the vanilla wafers and sliced bananas in a large baking pan. Allow to cool then add the meringue. To make the meringue, whisk the egg whites and cream of tartar until you reach stiff peaks. Gradually add 1 cup of sugar while whisking, then add the vanilla extract. Add meringue to the cooled pudding and bake at 375 degrees just until browned (should only take a few minutes so don’t walk away from it).