Potatoes turn black when preparing scalloped potato dish?

I cut PEI potatoes in slices for scalloped potatoes, but when they came out of the oven the top layer was a slightly gray black colour.

Answer :

Hello,

If you use PEI (Prince Edward Island) potatoes, then try to use the white potato variety. If the top layer of your scalloped potatoes turn black or gray when cooked then you need to cover the top layer of the potatoes with more sauce.

If you slice potatoes for later use, you can keep them in the refrigerator until you are ready to use them. Just slice potatoes and let them stand in cold water so they do not turn black.