Michigan Farmer Potato Cakes

2 cups of leftover mashed potatoes
1 large egg, beaten
1 tablespoon of flour, more the potatoes are thin
2 tablespoons of cream, less if the potatoes are thin
1 tablespoon of finely chopped onion
Butter

Mix all the ingredients except the butter.

Heat the butter in a skillet.

Drop tablespoons of the potato mixture into the hot butter and brown on both sides.