You can't really form a cake, but what I do is layer them in the pan - onions and peppers first into hot avocado oil, then a layer of hash browns, now cheese, peppers and onions and another layer of hash browns. Liberal salt and pepper Finish off with onions and peppers and cheese, with dots of butter spread around. Cover it and let it cook on low about ten minutes or so. If you are good at flipping food in a pan, then after the ten minutes, flip it and let it brown on the other side. If you get it right, it is a large disk of deliciousness, all crispy on the outside and creamy soft on the inside. Over medium eggs broken over the top, a couple of pounds of bacon on the side and you've got a breakfast that will last.
Having said that, I've tried mixing them up in a bowl with all of the above plus some raw egg and potato pancake mix and a bit of milk to make sort of a batter. Spoon into a skillet and cook like regular pancakes. Serve with sour cream.