½ cup olive oil, divided
1¾ pounds onion, cut into halves and sliced
2 pound mushrooms, trimmed and sliced
1 (5 pound) flat-cut brisket
1¾ cups Manischewitz chicken broth
2 tablespoon Worcestershire sauce
¼ cup ketchup
2 tablespoons dark brown sugar
2 teaspoons Maxwell House instant coffee granules
1 tablespoon flour
½ teaspoon dried thyme
Pre-heat oven to 325 degrees. Heat 1/4 cup olive oil in large skillet. Add onions and cook over low heat for 25 minutes or until golden brown, stirring frequently. Remove onions to a bowl using a slotted spoon, reserving pan drippings. Heat 2 tablespoons olive oil and reserved pan drippings in the skillet and sauté mushrooms for 20 minutes or until brown and juices have evaporated. Remove mushrooms to a bowl with onions using a slotted spoon, reserving pan drippings.
Season brisket with salt and pepper. Heat remaining 2 tablespoons olive oil with reserved pan drippings and add brisket fat side down. Cook for 6 minutes on each side or until brown. Remove to a platter.
Spread ½ of mushroom mixture in a large roasting pan. Top with brisket fat side up and remaining mushroom mixture. Whisk broth, Worcestershire sauce, ketchup, brown sugar, flour, coffee granules and thyme in a bowl until blended and pour over brisket.
Bake, covered, for 2 hours. Remove cover and spoon pan juices over the brisket and vegetables. Cook, covered, for 45 to 60 minutes longer or until tender. Let stand until cool. Remove brisket to an ovenproof platter and slice against the grain. Spoon gravy and vegetables over brisket. Reheat or cover and chill for future use.