It's traditionally cooked on a flat basalt stone (caco) instead of in an oven — the bread is literally named after the volcanic rock it's baked on.
A dense, round sweet-potato flatbread is griddled on a hot stone until lightly charred, split open and slathered with garlic-and-herb butter while still warm. Sold hot off the griddle at Funchal's markets and street stalls, often folded around a piece of grilled meat.