1Preheat oven to 350°F.
2Place sheet of heavy-duty aluminum foil in shallow roasting pan with foil extending 6 inches beyond pan on either side. Spray with no-stick cooking spray. Place brisket fat-side down in middle of foil.
3Combine dry onion soup mix with jelly and cocktail sauce in medium bowl. Pour half of mixture over brisket; turn brisket fat- side up, covering with remaining onion mixture. Bring both sides of foil to middle and fold foil down on itself several times.
4Repeat with two remaining sides. Bake 3 hours or until fork- tender. Remove from oven. (Brisket can be cooled and held in refrigerator overnight at this point.)
5In 10-inch skillet melt 2 tablespoons butter; sauté mushrooms and onions 5 to 8 minutes or until light golden brown.
6Remove brisket from pan; pour off juices, skimming fat off top. Remove layer of fat from brisket. Slice meat across grain into thin slices. Return meat to roaster. Top meat with mushroom mixture, meat juices and tarragon. Cover with foil. Return to oven to heat through before serving.
source: Family Features