Step 1

Place unopened can of condensed milk in a large pot; cover with water. Bring to boil; reduce to a simmer. Cover pot with lid and simmer for 3 hours to make the toffee, checking periodically to ensure the can is still immersed and adding more water as needed.

Step 2

Remove can from the pot and allow to cool until safe to handle. Rinse with cold running water for 10 minutes to speed up cooling.

Step 3

Open carefully and stir toffee until smooth. Spread toffee over the bottom of the prepared graham pie crust. Chill for at least 1 hour.

Step 4

Layer sliced bananas on top of the toffee. Beat cream in a large bowl until soft peaks form. Add sugar and continue to beat until fluffy. Spread whipped cream over bananas.