In a small bowl mix together 3 tablespoons of honey and 5 tablespoons of whole grain mustard.
Make several slits into the surface of the meat joint. Season with salt and pepper and rub the honey and mustard mixture into the surface of the meat.
Open up a Bakewell Extra Large oven bag and place the meat inside the bag.
For extra flavour place the bag in the fridge for 24 hours to marinate the meat before cooking.
Take the meat out of the fridge to stand for 30 minutes before cooking (to get the meat to room temperature before cooking).
Preheat the oven to gas mark 4/180°C/350°F.
Open up the oven bag and place three sprigs of rosemary into the surface of the meat.
Add to the bag 2 chopped red onions, 2 chopped carrots and 2 large potatoes cut into quarters.
Tie the bag loosely with one of the ties provided and place the bag into an oven proof dish.
Place the dish in the middle of the oven (making sure the bag doesn’t touch the sides or element).
For medium results cook for: 25 min per 450g (1lb) + 25 min. For well done results cook for: 30 min per 450g (1lb) + 30 min.
Once the time is up and food is cooked carefully remove from the bag and serve.