01 -
In a large bowl, combine your leftover mashed potatoes, chopped cooked vegetables, and diced onion until well mixed.
02 -
Heat the butter and olive oil together in a large frying pan over medium heat until the butter is melted and bubbling.
03 -
Add your potato mixture to the hot pan, spreading it out into an even layer. Let it cook undisturbed for 10-15 minutes until you get a lovely golden-brown crust on the bottom.
04 -
Carefully flip the mixture over (don't worry if it breaks a bit!) and cook for another 5-10 minutes until golden brown and crispy on both sides.
05 -
Season generously with salt and pepper to taste. Serve piping hot while the edges are still crispy!