Cockles and laverbread is a Welsh coastal pairing in which the seaweed leads and the shellfish answers it. Laverbread is not bread at all: it is laver, a soft purple-black seaweed gathered off the Gower and South Wales coast, boiled down for hours into a dark, smooth, intensely savoury purée that tastes of iodine, salt, and the sea floor. Cockles are small, sweet, briny bivalves dug from the same sands. Put together on toast, the laverbread is the dominant note, a thick mineral spread, and the cockles are the bright, chewy, slightly sweet counterpoint set into it. The defining fact of this dish is that the laver is the lead ingredient rather than a condiment, which is unusual for any seaweed in a Western kitchen and is what makes the pairing specifically Welsh.
The craft is in the laverbread and the base under it. The purée is wet and dense, so it is taken to a thick, spreadable consistency and laid on toast firm enough to act as a plate, often after being rolled in oatmeal and fried so it sets and gains a savoury crust rather than sitting as a slick. The cockles are added cooked and well drained, because they carry their own brine and any extra liquid loosens the laver into a smear. Bacon frequently joins them, and it is not incidental: its smoke and fat lift the iodine depth of the laver and the salt of the cockles into something rounded, which is why the classic Welsh breakfast plate sets all three together. The bread is plain and firm because the laver is loud and complicated on its own and a strong loaf would only argue with it.
The variations stay on the Welsh coast and in the breakfast register. Laverbread fried in oatmeal and served with bacon and cockles is the canonical full plate translated onto toast. Laverbread alone on hot buttered toast is the spread at its most essential. Cockles dressed only with vinegar and pepper are the shellfish met without the seaweed at all. Each of those is its own dish and deserves its own article rather than being crowded in here.