Prepare the joint by seasoning by rubbing salt, pepper and grated nutmeg all over the meat.
Heat a little olive oil in a large pan and allow the sliced vegetables to sweat for 5-10 minutes, then transfer to a casserole dish.
Brown the meat in the pan used for the vegetables then transfer to the casserole dish. Combine the mustard, herbs with the stock and wine and pour around the joint.
Cover the dish and cook for about 2 hours. Add a little more stock or wine during cooking as necessary.
When the joint is cooked remove from the oven and keep warm. Meanwhile, strain the contents of the casserole dish and discard the vegetables. Place the liquid into a saucepan and allow to reduce slightly.
Add the rowan berry jelly and stir until it melts.
Mix the corn flour with enough water to form a liquid then slowly add to the sauce stirring constantly until the mixture blends and becomes glossy. Allow this to cook for 2-3 minutes.
To serve, carve the joint onto warmed plates and drizzle the sauce over