Oven sirloin joint is the Sunday centrepiece — a carvery roast with crisp fat, pink slices, and gravy from the tray. Sirloin Joint 1kg is the neat midweek roast; Sirloin Joint 2-2.2kg (Frozen) is the bigger freezer joint when the table fills. Shop both in beef joints and Sunday roast.
Oven method
Take the joint out of the fridge an hour before roasting. Pat dry, score the fat lightly, and rub with oil, salt, pepper and a little mustard or garlic. Sit on a rack over a tray with onions and a splash of stock underneath. Preheat the oven to 220°C and blast 20 minutes to colour, then drop to 180°C (fan 160°C) and roast about 20 minutes per 500g for pink, or longer for well done — always finish by probe: around 52–55°C for rare-pink or 57–60°C for medium-pink in the thickest part, rising a few degrees as it rests. Rest 20 to 25 minutes tented with foil before carving. Do not skip the rest or the board floods. Baste once with tray juices. If the fat is pale near the end, a short hot blast crisps it. Carve across the grain in thin slices. Save the tray liquor for gravy — skim fat, then thicken with a spoon of flour or cornflour.
Leftover and steak backup
Cold sirloin the next day makes proper sandwiches with horseradish. For steak nights instead of a joint, browse sirloin steaks and beef steaks for ready-cut packs.
What to serve
Roast potatoes, Yorkshire puddings, and seasonal greens, or cold with pickles and bread. Leftover beef freezes well sliced in gravy; thaw overnight and reheat gently. Use scraps in fried rice or hash.
Times above are a guide for home ovens, air fryers and pans — always trust a probe over the clock, and rest meat before you carve so the juices stay in the slice, not on the board. British packs vary a little in thickness, so start checking a few minutes early the first time you cook a new size.
Write your own fridge note the first time you cook a new pack size — home ovens and pans vary, and a two-minute early check beats dry meat. Rest on a warm plate, not a cold board, so the juices stay put when you carve or plate up.