1. Potatoes can be boiled or baked (baked is best). Skin and mash potatoes with the butter or soured cream.
2. Butter an oven-proof dish and proceed to put a layer of potato, then a layer of laver, layer of potato, layer of laver etc., until the dish is full.
3. Top with potato. Heat in the oven and then place under a hot grill until the potato is brown on top.