
In a large sauce pan, mix the milk and heavy cream and bring to a boil, letting it bubble for at least 30 seconds before taking the cream off the heat. Set it aside to cool for 1 minute.
Temper the egg mixture by pouring a fourth of the hot milk into the eggs in a slow and steady stream, whisking vigorously as you go until you have a milky yellow liquid.
Pour another fourth of the liquid into the egg mixture and whisk vigorously, until well combined. Pour the liquid back into the sauce pan with the remaining cream and place the pan back onto medium-low heat. Stir in the sifted flour or cornstarch.
In a large glass bowl, dish, or eight 8oz cups, layer the pudding in this order: a third of the whipped cream, a third of the wafers, half of the pudding, and half of the bananas. Repeat layers once more and top the pudding with vanilla wafers along the edge of the bowl, whipped cream in the middle, and vanilla wafer crumbs or cookies on top.
If desired, top with ground cinnamon and/or grated nutmeg.