Pudding: Separate the yolks from 3 eggs and add remaining whole egg to yolks. Whisk until smooth.
In a saucepan whisk together 1/2 cup sugar, the flour, milk, and salt. Bring to a gentle boil then reduce heat to simmer.
While whisking the eggs, scoop a bit of the hot milk mixture and slowly pour into the eggs. Once the eggs are warmed, add the egg mixture into the pan with the remaining milk. Cook over medium heat until thick (about 8-10 minutes). Remove pudding from heat and add vanilla.
When ready to cook, start the Traeger on Smoke with lid open until fire is established (4-5 minutes). Set temperature to High and preheat, lid closed, for 10 to 15 minutes.
Place a medium cast iron pan on the grill and warm. Once the pan is hot, add butter and bananas and saute until bananas are lightly browned. Be careful not to take them too far or they will turn into mush and fall apart.
Once bananas are browned, sprinkle with brown sugar and stir allowing sugar to melt. When sugar is melted, remove the cast iron from the heat and add whiskey. Return the pan to the grill and reduce liquid until syrupy and bananas are coated. This should only take a couple of minutes.
To assemble, place a couple tablespoons of the pudding in the bottom of a mason jar, top with banana mixture and a bit of the Nilla wafers. Repeat the layering process until the jar is filled.
Finish with a dollop of whipped cream and serve. Enjoy!