ABOUT BOILING THE CANS OF CONDENSED MILK
Over the years I have become increasingly concerned about the danger of boiling cans of condensed milk. There is no danger of them exploding unless the water in the saucepan boils dry. If this does happen the result is terrifying and can scald anyone close to it. It has happened to me once and that was enough. Because I now teach and demonstrate a lot I like to make sure my instructions are safe so I have devised this method.

Find a deep saucepan or casserole that will go in the oven. Put into it as many tins as will fit. (THE TINS MUST BE UNOPENED).
It worth doing several at a time to save on power.
Cover the tins with water and bring to the boil.
Cover with a lid and transfer to the oven set to gas mark 1 / 140 C (less for fan assisted).
Cook for 3 ˝ hours.
This way there is no danger of the water boiling dry and being in a more controlled temperature you get a more consistent result.
Lift the cans from the water, cool and store.

An unusual bonus comes from storing these tins over a period. After some months sugar crystals begin to form in the toffee and you get crunchy banoffi - mmmmm.