Beef rump with smashed potatoes & anchovy vinaigrette

Place potatoes in a saucepan of cold salted water; bring to the boil. Cook potatoes for 20 minutes or until tender. Drain well; pat dry with paper towel. Cool slightly; press down on potatoes to split slightly. Place potatoes on an oven tray.

Meanwhile, bring beef to room temperature. Preheat oven to 120°(100°C fan). Place a wire rack over a large roasting pan.

Using a small sharp knife, score lines 5mm apart into the fat layer of the beef. Sprinkle with half the salt flakes and half the pepper. Heat 1 tablespoon of the oil in a large frying pan over high heat; cook beef, fat-side down, for 5 minutes or until golden. Turn; cook until browned all over. Place beef on rack in roasting pan. Pour excess beef fat from frying pan over potatoes on tray; toss to coat, then season with remaining salt and pepper.

Roast beef for 3½ hours for medium-rare (see notes) or until cooked to your liking; roast potatoes alongside beef for last 30 minutes. Remove beef from oven; rest, covered loosely with foil, for 30 minutes.

While beef is resting, increase oven to 240°C (220°C fan); roast potatoes for a further 15 minutes or until golden and crisp.

Seed chillies. Finely chop chillies with anchovies. Process or blend anchovy mixture with oregano, vinegar and remaining oil until combined.

Spoon vinaigrette on beef; slice beef, serve with potatoes, topped with extra oregano.