You may know these as 'Oca', in New Zealand they're called yams.
The yam is a small potato-like tuber and comes in several bright colours, from pale creamy-yellow to rose to purple-red and apricot!
The have a knobby, shiny, waxy edible skin and firm potato-like flesh and slightly acidic flavour. The flavour is slightly tangy, and texture ranges from crunchy (like a carrot) when raw or undercooked, to starchy or mealy when cooked.
Bake, boil, roast, fork-mash or use in any dish calling for potatoes. And there's no need to peel the skin!