This Product has been around for 20 or more years.
it has a pin you put 3 spikes around the outer shell
and after 5 to 8 mins the Curry or Whatever Food.
Each can has a bit of metal - the spike to stick in to activate the
Water and Limescale outside the inner can.
Demo was on Sunday Brunch Ch4
This Product in a hot day would cook faster
of course.