1. Preheat oven to 170°C, fan-forced. Line a large roasting pan with foil and arrange orange slices over the base. Open butterflied roast onto a board, with the fat-cap down, and allow to come to room temperature for 20 mins.

2. In a medium bowl, combine dried cranberries, breadcrumbs, onion, rosemary and orange juice. Season with salt and pepper, and mix well.

3. Season the inside surface of the roast with a good pinch of salt and pepper. Spread stuffing evenly over beef, leaving a 2 cm border around the edges. Roll tightly to enclose, and with the fat-cap on top, secure with string or food grade bands every 3 cm.

4. Transfer tied roast to the pan and place on top of the orange slices. Combine oil and mustard in a small bowl and spread over the top of the roast.

Roast the beef for 60 mins. Remove from oven, cover loosely with foil, and rest for 10 mins. Carve into rounds, removing ties as you slice. Serve with pan juices.