I'd call that a result!
wouldn't the cake tin fit inside the billy/oven the proper way up? Only going by the lid size in the last picture & the open oven pictures, it looks like it might, so long as its off the bottom it will work well...
I've done a fair bit of Alcohol baking I do mine on simmer with the ring fully open & pot lid on, no peeping slow bake for up to an hour... plenty of heat cooked through brown moist no burn
this was my first attempt
Dry Baking on my Trangia 25 in the large billy Top tip greaseproof paper to prevent sticking & saves on washing up,
Enamel plate makes a good baking tray. but with hindsight maybe not such a great idea as thermodynamically Aluminium is probably better than whatever material enamel plates are made from! bake time was reduced by about 10 minutes for a similar recipe (caramel cup cake) when the small aluminium billy was used as a cake tin
Betty Crockers Blueberry Muffin mix... mmmmm put me in the notion now...
Modified pot stand Goes in The larger Trangia billy to prevent burning..