My leftover mashed potatoes had some butternut squash (hence the orange hue), but you can certainly use a 100% percent potato mash too. Since you’re leftover potatoes already have salt and pepper, you probably won’t need to add any extra.
Extra virgin olive oil
1 small onion, chopped
1 quart leftover cold mashed potatoes
Cumin, to taste (I used about 1/4 teaspoon)
Heat a skillet, preferably cast iron, over medium heat. Add enough olive oil to coat bottom of pan. Add onions and saute 1 to 2 minutes until softened and fragrant.
Add mashed potatoes and cumin; stir to mix in onions. Increase heat to medium-high and press potato mixture down with a spatula to form a thin layer in the pan.
Cook until nicely browned and crisp, then flip using a heat-proof spatula, and continue cooking until underside is browned to desired doneness. Serve hot and enjoy (I sure did)!