I have no idea the exact amounts, and frankly they don't matter. It's melted butter (lots, and that is the technical term), sliced potatoes, and salt. That's all.
Potatoes, sliced really thin
Butter, melted, lots
Cast Iron or other non-stick pan
Brush the bottom with a generous amount of butter. Now add more, I meant REALLY generous. Add one layer of potatoes with the sides overlapping. Just one layer because you need to add more butter, a little sprinkle of salt and then on to the next layer. Do that, don't skimp on the butter or the salt. Also press down between the layers to compact it a bit.
Heat on the stove to brown the bottom and edges until you start to hear it sizzling. Then but a lid on the top and place in the oven. Bake for 45 minutes to an hour until the potatoes are completely tender.
Use a rubber spatula to loosen the potatoes from the side and the bottom if you can. Invert on to a plate and serve. Or serve it in the pan you baked it in, it will taste the same either way.