The coulotte is the cap muscle that sits on top of the sirloin, near the rump. It comes with a thick fat cap on one side, and that fat is the point: it bastes the meat as it cooks. In Brazilian churrascarias it is called picanha, and it is the cut most people remember.
Leave the fat cap on and score it lightly. Season simply with coarse salt, or use a dry rub. You can grill it whole over indirect heat and finish over direct heat to render the fat, or cut it into thick steaks with the grain and then slice against the grain to serve. Churrasco-style, fold thick slices into a C shape on a skewer, fat side out, and grill until the fat crisps. Rest it for 5 to 10 minutes before slicing.
From Carter Ranch. Our cattle are 100% grass-fed and grass-finished, raised 4-8 years on native grasses in the Big Horn Mountains near Ten Sleep, Wyoming.
We call it double-aged: the animal and the beef. Our cattle are 4 to 8 years old, and every steak and roast is wet-aged 30 days before freezing. That is what makes mature beef tender.