1. Place sweetened condensed milk cans into a large pot. Fill pot with water until cans are covered. Remove cans. Heat water to a gentle boil over medium to medium-high heat. When water is just about to boil, place cans into water using tongs.
2. Boil cans for 3 hours uncovered. You will need to check the water level every half hour. The cans need to stay submerged to keep them from exploding. Add water as needed. When finished, place the pot (with cans) in sink and run cool water into the pot to help cool the cans down. After about 15 minutes the cans will be cool enough to handle.
3. Take the cans out and set aside in the refrigerator until completely cooled.
4. Preheat oven to 350 degrees F.
5. Place graham crackers into a Ziploc bag and crush until fine crumbs are reached. Reserve 2 tablespoons of the crumbs. Combine graham cracker crumbs and melted butter in a bowl using a fork. Pour crumb mixture into pie plate and press to coat bottom and sides of plate. Bake for 7-12 minutes. Remove from oven and cool.
6. While pie crust cools, whip together heavy cream, confectioner’s sugar, and vanilla until fairly stiff peaks are formed. Set aside in refrigerator.
7. Peel bananas and cut into ¼″ slices. You want to make sure the bananas are not so thin that they will disappear into the pie.

To assemble:

1. Open one toffee can and pour into cooled pie crust. Spread evenly. Cover the toffee with banana slices. Pour the second con of toffee over the bananas and spread evenly. Top the pie with the whipped cream, spreading it to the edges of the pie plate. Sprinkle the reserved graham cracker crumbs over the whipped cream.
2. Refrigerate pie at least 30 minutes before serving to make sure everything is set.