Directions

1. Boil the potatoes and mash (you can also use leftover mash potatoes if you prefer).
2. Sauté the onion in oil until very soft.
3. Mix the sautéed onions and egg yolks into the mashed potatoes.
4. Shape the potato mixture into equal sized balls. Poke a hole in each ball, stuff with the grated cheese and then seal the hole.
5. Flatten each ball into patties and place them in the refrigerator to chill for 45 minutes (they do not need to be chilled but they hold together better when sautéing if chilled).
6. Sauté patties in oil until nicely browned.