Ahh, Baby's Heads...
Best from the 'larger' can as found in the 4 or 10 man rat packs (you got a much smaller one in the 24hr rat pack).
Place can (sealed) on it's end in a mess tin of boiling water, heat until the end 'pops' out. Then remove from the water, point in a safe direction (normally towards some poor unsuspecting victim) and pierce with a tool of choice... the marlin spike on a jacknife RE was pretty good...
Allow pressure to vent and then remove both ends of the tin. Now push the mess in the tin halfway out and using the end of the tin as a guide neatly slice in half and place it on the plate, open end up, push the remaining half out and place on plate in a similar manner. Dress it appropriately with ketchup.
It looks just like a sliced open baby's head, even better with ketchup dripping down the side
hence the name.
Also good was the stewed steak, I used to make a brill cottage pie with it when out sailing, served up piping hot at midnight, kept the cold out and the duty watch awake.