I don't know if it's proper, but this works;
Approx. 2 C. mashed potatoes
1 egg, beaten
salt, pepper, (grated cheese), (chopped onion)
Mix all together, form into four patties. dredge in flour, saute in a pan with bacon fat, oil, butter or whatever you have.
If you have a problem with them being runny, try mixing a tablespoon of flour in the potatoes, but the egg usually takes away any runnyness.