Pudding in the Thermos Cooker

I used some of the blueberries I picked to make a clafootie type pudding and tried out the thermos cooker I bought to cook it.  I used my Shuttle Chef thermos Cooker as a bain marie (water bath) and my tiffin pots as the bake pan.  It worked as well as anything except the bottom tiffin pot leaked.  Not much harm done.  I just poured out the water on top and the pudding is fine.  I got the Shuttle Chef cooker because the interior pot is a very high quality stainless pot with a thick bottom for heat dispersion and its superior insulating qualities.  Not easy to find anymore.  I ended up ordering it from a Canadian supplier which triggered my credit card fraud alert.  Nothing wrong with the vendor tho, just automatic software.