I confess, I've planned mashed potatoes for dinner before just so that there are leftovers to make these potato cakes for breakfast on the weekend. I make them with the Garlic-Mashed Potatoes that I also posted on Food52. (They haven't turned out as well when I've tried them them with thinner leftover potatoes.) —pantryhero
small yellow onion, finely chopped (about 1/3 cup)
Heat 1 teaspoon of the butter in a small non-stick pan over medium heat. Sauté the onion with a pinch of kosher salt until the onion is soft and translucent but not brown, about 5 minutes. Turn down the heat if the onion starts to cook too quickly.
Thoroughly mix the cooked onion and chopped chives with the leftover mashed potatoes.
Heat the remaining 1 1/2 teaspoons of butter with the olive oil in a medium griddle pan or non-stick pan over medium heat. Meanwhile, shape the potato mixture into 4 patties, each about 3" in diameter.
When the griddle is hot, cook the patties until golden brown and crispy, flipping once, about 3-5 minutes per side. They can be a hard to flip, so lift them up a little to make sure the bottoms are brown enough, and when they're ready, really shove your spatula under there. Serve immediately