I have used this recipe for many years. This year I did not cover the meat the first 2 hours, it turned out really good.
Mix brown 3 heaping tablespoons of brown sugar with yellow mustard and about 1 T garlic powder. If your brisket does not come with pickling spices, you will need about 2 T of pickling spice tied up in cheese cloth with cotton string.
Preheat oven to 325 degrees then put the brisket into a 13X9 baking dish, add the juice from the package to the pan, add about 1/2 cup of water to the pan. Slather the meat with mixture, on both sides and on the sides. Add 2 stalks of cut of celery, and half an onion cut into quarters. You will fish these out later. Set the timer for 2 hours. The brisket will be developing a nice glaze, baste the meat a few times. Then when the timer goes off, fish out the cooked veggies and then add new carrots, and potatoes, onoions and fresh garlic clove sliced. cover with foil and let it cook another hour. Pull it out and add cut up cabbage to the roasting dish pushing the cabbage into the juices. Cover and put back into the oven for another 30 mintues to cook the cabbage. Total hours should be between 3 1/2 hours to 4 hours.Remove from the oven, place the brisket on a wooden cutting board, and put the veggies into their dishes to serve. Slice the brisket across the grain in about 1/8 slices. Makes great sandwhiches! Serve the meat with different coarse grain mustards and horseradish.