According to The Big Feed, crispy seaweed is made from cabbage or spring greens. Abel & Cole point out that kale is sometimes used as well. In any case, seaweed is not an ingredient of the dish.
Crispy seaweed is often prepared in the oven, but some recipes call for it to be deep-fried. The leaves are cooked with salt and sugar, and sunflower or olive oil is occasionally added. The vegetables are cooked until they are crisp and dark green. Certain recipes call for toasted nuts, pine kernels or dried fried fish to be sprinkled over the cooked greens. The crispy seaweed is eaten alone or used as a topping.