chorizo
Spanish or Portuguese pork sausage, heavily seasoned with paprika and garlic, which releases red fat as it cooks.
Dry-cured chorizo for slicing is sold in most supermarkets, while the softer cooking chorizo meant for stews and frying is more often found at a butcher's counter, in Spanish or Portuguese delis, or by mail order. It is the better choice for braises because it gives up more fat and paprika flavour to the sauce.
Substitute:
Cured chorizo cut into chunks works at a pinch, though it turns chewier and renders less fat; Mexican chorizo is a different product, loose, seasoned with vinegar and chilli, and changes the dish noticeably.