Boil potatoes, until just tender but not cooked all the way through, about 20-25 minutes. Drain, cool, peel, and cut into 1/4 inch thick slices. (you could leave the peels on if you want, to get all of the nutrition from the potatoe
Preheat oven to 350.
In a greased 9 x 13 dish, layer half of potato slices, then top with half the bacon and onions.
Stir milk into sour cream and season with salt and pepper. Spread half the mixture over the potato layer and then sprinkle with half the cheese. Season with salt and pepper. Repeat layers.
Mix Panko bread crumbs together with melted butter, sprinkle over top of casserole and Bake uncovered for 30 minutes until golden and bubbly. Serve hot.