To prepare the pudding:

1. Whisk the sugar, flour, and salt together in a medium saucepan. Gradually whisk in the milk until combined, then place the pan over medium heat. Heat the milk mixture, stirring regularly, until thickened to a creamy salad dressing consistency and gently bubbling, 8 to 12 minutes. Cook, stirring constantly, for 2 minutes more. Place the egg yolks in a medium bowl. While whisking the yolks vigorously, slowly drizzle in the milk mixture. Once combined, pour the mixture back into the saucepan and place back over medium heat. It will be pale yellow, and just barely thicker than heavy cream consistency. Cook, stirring constantly, for 2 minutes more. Remove from the heat. Stir in the vanilla and butter until melted and combined. At this point, the mixture will be back to that creamy salad dressing consistency (think: runny ranch) and just a bit more saturated yellow in color.
2. Sprinkle half of the crumbled vanilla wafers into a 1 1/2- or 2-quart baking dish, or the bottom of 8 (6-ounce) jars. Place half of the banana mixture over the crumbled wafers. Dollop half of the warm pudding over the bananas, or fill each jar to its halfway mark with half of the pudding.
3. Repeat layering. Repeat the layering process once more with the remaining wafers, bananas, and pudding. Cover the baking dish or each jar with a sheet of plastic wrap (press it directly onto the pudding if you don’t want a skin to form). Refrigerate until chilled, at least 2 hours. Top with whipped cream or meringue, and more crumbled cookies, if desired.
4. To prepare the caramelized bananas:
5. Combine the butter, brown sugar, and cinnamon in a frying pan over medium heat to melt and combine. Once melted, add the sliced bananas in a single layer in the pan and lower the heat to medium-low. Cook on each side for 1 minute and then remove the pan from heat. Allow to cool slightly before layering in with the pudding.