Every time I make mashed potatoes, I inevitably end up with tons leftover. I think we all have the tendency to think, "well, everybody loves mashed potatoes!" Yes, that's totally true, but we also forget that we're probably serving the potatoes alongside a pot roast or Thanksgiving dinner, so even if we love mashed potatoes, there isn't that much room for them after turkey, stuffing, Brussels sprouts, lots of wine, etc. My rule of thumb is to have no more than one creamer potato a person, but even then, a whole potato per person is still a pretty filling serving. There are worse things than leftover mashed potatoes, though. Perhaps my favorite way to make use of the excess is to just eat them cold, the morning after for breakfast (go ahead, judge), but number two would be to turn them into crispy-on-the-outside and creamy-in-the-center potato pancakes.
Anyone who's ever made a tasty potato pancake knows that there are a few essentials-- oniony flavor, crispy outsides, and a dollop of sour cream on top. That said, when you're working with leftovers, sometimes you have to get creative. In digging through my fridge today, I had no onions, but did have a leftover leek from my sister's Thanksgiving casserole. I had no sour cream, but did have some Greek yogurt. And that's the beauty of this kind of cooking-- you're forced to get resourceful, usually with tastier results that you could have planned.
I can't quite give you a recipe, but here's what I did for these potato pancakes: I chopped up one leek and sauteed it in some olive oil and seasoned with salt. Then, I mixed the cooked leek with about 3 cups of mashed potatoes, 1/2 cup of shredded cheddar cheese, 1 egg, a few tablespoons of all purpose flour to firm up the mixture, and some spices-- a dash of paprika and another of cayenne. Then, I shaped small portions into pancakes (probably about 1/3 cup "batter" per pancake) and places gently into my heated skillet. There's no need for butter or oil when you're frying, provided you put plenty of butter in your mashed potatoes, as you should. I let them fry up until crispy on one side-- this might take longer than you expect-- and then flipped! Serve warm with sour cream or a spot of Greek yogurt. I also like to splash hot sauce all over!