Unclefrank,
I just followed the recipe so I think the look of the potatoes comes from the turmeric.
As a recent convert to being a vegetarian (health reasons) I've dabbled with swapping out chicken for veggies in some of my fave recipes (Madras, Jalfrezi etc).
I've found that dry cooking unpeeled potato chunks in a wok with turmeric and water for a while until they are half cooked and then using 'as if' it was prepared chicken works a treat. The potatoes have a nice earthy roasted 'feel' and don't fall apart as much as par boiled and such.