Place an unopened can of condensed milk in a large pot and fill the pot with water until the can is completely submerged. Bring the water to a boil. Once boiling, reduce the heat to a simmer and let it simmer for 4 hours. Be sure to check and add water to the pot every 30 minutes to an hour to keep the can covered.
Once done, carefully remove the can from the pot and allow it to cool. Set it aside.
Preheat your oven to 350°F (175°C).
Crush the arrowroot cookies using a food processor or by placing them in a sealed plastic bag and using a rolling pin to crush them.
Transfer the crushed arrowroot cookies to a mixing bowl and pour in the melted butter. Mix until all the cookie crumbs are coated with butter and the texture changes slightly.
Press the cookie mixture into a pie dish with raised sides.
Sprinkle cinnamon evenly over the crust and place it in the preheated oven for 10 minutes.
In a separate bowl, combine the whipping cream and vanilla extract until it reaches the desired consistency. It should hold its shape when the bowl is tilted. Place it in the fridge until you're ready to assemble the pie.
Slice the bananas into even 1/2-inch thick slices.
Allow the pie crust to cool completely after removing it from the oven.
Once the caramel from the can has cooled, transfer it to a separate bowl and stir in the lemon juice. This will slightly thin the caramel.
Spread the caramel evenly on top of the cooled pie crust.
Add a layer of banana slices evenly over the caramel.
Next, add the whipped cream as another layer.
Finally, sprinkle the chopped up chocolate flake bar on top of the pie.
Place the pie in the refrigerator for at least 6 hours before serving. For best results, leave it in the fridge overnight.