How do I cook a joint of rolled brisket?

Last time I cooked it it was tough, and I hope someone will tell me how to cook it so it is tender, nothing fancy just a roast.
Answers:
Use to pot roast! Place in dish,add beef stock,seasonal veg. Cover with lid.Cook on number 3 gas,for 3-4 hours. OR, try this:
4-5 lb lean beef brisket
Seasoned salt
4-5 medium onions, chopped
3 garlic cloves, minced or pressed
1 bottle (750ml) red Burgundy wine
1 cup water
3-4 Tbsp tomato paste
1 Tbsp Worcestershire sauce
Salt and freshly ground pepper to taste
Preheat oven to 500 degrees F. Sprinkle the brisket
generously with seasoned salt, and place it fat side up in a
heavy roasting pan or kettle that can go into the oven.
Roast uncovered for 25 to 35 minutes or until browned.
Sprinkle the onions evenly over the top of the meat. Stir
together the garlic, Burgundy, water, tomato paste, and
Worcestershire sauce. Pour the liquid around the meat and
cover the pan. Lower the oven temperature to 325 degrees F.
and continue cooking for 4 hours or longer until very
tender.
Lift the meat from the liquid, and allow to rest for 20
minutes before slicing. Meanwhile, use a slotted spoon to
transfer the onions to a blender or food mill, reserving all
the pan juices. Process to a smooth sauce, adding just
enough of the reserved liquid to thin to the desired
consistency.
To serve, carve the meat across the grain. Arrange the
slices on a warm platter, and spoon sauce over them to coat
evenly. Serve extra sauce on the side.Yummy!!
cook it slow. reduce the heat a bit. and cover the beef with foil to keep it more moist
SLOWLY with water in the roasting pan and lid on.
Roasting essentials
Position the oven shelves so the meat is in the centre of the oven.
Place the joint uncovered on a wire rack in a roasting tin ensuring any fat is on the top. This allows the juices to run down and baste the joint naturally.
When roasting beef and lamb joints, the secret is to cook the joints in a moderate oven for slightly longer to ensure even cooking.
Remember to weigh beef and lamb joints before calculating your preferred cooking time.
Oven Roasting:Gas mark 4-5, 180-190°C, 350-375°F
Beef Cuts Cooking time
Joints:
Sirloin, Rib, Topside, Brisket, Silverside, Mini joints Rare: 20mins per 450g (1lb) +20 mins
Internal temp approx 60°C
Medium: 25mins per 450g (1lb) +25 mins
Internal temp approx 70°C
Well-done: 30mins per 450g (1lb)+30 mins
Internal temp approx 80°C
In a casserole dish 2 beef oxo cubes just cover with water gas mark three for at least 3 hours more if possible be really tender!!
Put in a casserole dish with half a pint of water and cook in the oven for about two and a half hours at around 180c.
You can slow roast brisket.

The best way to cook it is to pot roast it. You need a pot with a tightly fitting lid. A casserole dish will do, but a Dutch roasting pot is better. Make up about a cup full of stock (watered down gravy is fine) and put it in the pot with the meat. Put a couple of slices of onion on top of the meat (that helps tenderise it) and put it in the oven at gas mark 3 for one hour per pound of meat (or 2 hours per kilogram). Then invite me to dinner.
Usually do mine in a pressure cooker - see the info that came with it if you have one. It saves on time and energy and you can cook the vegetables in the pan at the same time ! enjoy !
We make ours in a crockpot. Talk about tender! A couple cups of water, the spice packet, a couple bay leaves and a beer. Slap the lid on, turn it on high and walk away for a while!
If you have a slow cooker and about six hours, you'll have the best brisket ever! Just place it in there with a half cup of water or chicken broth, season the crap out of it, put the lid on and turn it on low, then forget about it! check it after 4 hours, but leave it in for six to eight. Yum.
yes what Jane said exactly but i will add for 3-4 hrs on gas mark 3
cook very slowly.in some water..sometimes i cook over night if its a big joint..leave to go cold then slice. this is not a roasting joint. so needs to be cooked with liquid, as a pot roast.
If it was tough you probably just didn't cook it long enough. You cook it slow for a loooonnnnnggg time (like maybe 3-4 hours) until eventually it gets soft. Here's the easiest and best recipe I've ever tried!

Mix 1 litre of ginger ale, 1 cup of tomato ketchup 1 packet of french onion soup mix. Pour over the top of the meat and cook COVERED for 3-4 hours on a low-med heat.
Pot roast. Make up some stock, chop oniions, carrot, celery, or any other veg you like. Place beef on top and cover with a well fitting lid. Cook slowly in moderate oven for at least 2 hours, the longer the better. Lovely tender joint