I think I might have sussed this one! My mum lived in NZ for years and calls em Kumara (apparently they have 3 types over there). She does them roasted in olive oil with Sunday lunch (unbelievably lush...) but she doesn't peel them - I think this is the key (even though she doesn't eat the skin but I do). We gave one large 'end' chunk (roast potato sizeish) to LO and he grasped the jacket whilst sucking out the molten ambrosia (am wondering if this might work with baked potatoes too as he loves new potatoes). He even ate another one for lunch the day after!