- Preheat the oven to Gas mark 4-5, 180-190°C, 350-375°F.
- Place the joint on a chopping board and make several slashes over the surface.. Season and rub the joint on both sides with the rosemary, pressing into the slits.
- Place the joint on a metal rack in a large roasting tin and open roast for the preferred, calculated cooking time, basting occasionally with any rich meat juices.
- In a small bowl mix together the balsamic vinegar and cranberry or redcurrant sauce.
- During the last 15 minutes of cooking remove the joint from the oven and brush with the glaze. Return to the oven to finish cooking.
- Transfer the beef to a large plate or platter, cover with foil and leave to rest for 5-10 minutes.
- Meanwhile prepare the gravy; spoon off any excess oil from the tin, leaving about 30ml/2tbsp of any rich juices. Place the roasting tin over a medium heat and sprinkle over the flour. Stir well with a small whisk or spoon, add a little stock and stir again, scraping the base of the pan to release any sediment.
- Add the remaining stock, and any meat juices from the platter, adjust the seasoning if required and simmer for 8-10 minutes, stirring occasionally until reduced to a well-flavoured gravy. Strain before serving.