I occasionally have a problem with potatoes when I add them to wet gravy curry type dishes. The problem is not consistent, so I am not sure what I am doing wrong. Sometimes my potato chunks get very tender on the inside but remain firm on the outside. When I slice into a chunk, I can see a coloration difference between the soft inside and firm outside. The outside almost seems uncooked. But it is cooked. Ideally the whole potato chunk should become tender. Undercooking would result in a tender outside but firm inside. Any idea of what I am doing wrong or what reaction is causing this to happen?
Usually my recipes go like this: I am making a wet curry, I have added dry spices to oil, maybe tomatoes or whatever depending on the recipe. I toss in the potatoes and whatever other veg. I stir them in the oil and spices, then I add a liquid like yogurt or water depending on the recipe, I allow it to come to a boil, then I lower the heat and cover, stirring occasionally until the meat/veg including the potatoes are done. Why does this soft inside firm outside happen sometimes?
Sometimes I peel early and set the potatoes aside in a bowl of water, sometimes I don't. I don't think that's it, but maybe.