Fill large sauce pan 1/3 full of water and bring to a boil. Whisk egg yolks in a small bowl and set aside. Combine dry ingredients in a metal bowl (large enough to fit neatly over your saucepan), and place atop saucepan of boiling water and reduce heat to medium/low. Briskly stir in half & half until mixture begins to thicken slightly. Add egg yolks and continue stirring, scraping sides as you go. As pudding begins to thicken slightly again (and all lumps are gone), add heavy cream and continue stirring constantly over medium to medium/low heat until mixture resembles a quite thick pancake batter. Note: It is imperative that you constantly monitor heat to ensure pudding thickens properly without scalding. If it gets too hot, it will curdle, from which there is no recovery. So be patient. It will be worth it ;-)

Remove from heat and let rest for half hour or so before stirring in vanilla. Whisk pudding briefly before ladling into serving bowl. Layers should begin and end with Nilla wafers. Start by lining the bottom of your serving bowl with wafers. Slice bananas, evenly distributed, over wafers for next layer, then immediately ladle pudding over bananas (to minimize oxidation), thickly enough to completely cover bananas but not so much that they’re swimming in it. Continue layering to the top of serving bowl, ending with wafers on top. Cover serving bowl with plastic wrap, gently pressing wrap down so it actually touches the top of pudding and seals it (this prevents rubbery crust from forming on top as it chills). Chill thoroughly in refrigerator before serving (at least 2-3 hours). Enjoy!