1 tablespoon cornstarch dissolved in 2 tablespoons water
2 tablespoons water
Prepare couscous according to package directions.
Heat 1 tablespoon oil in Dutch oven over medium heat until hot.
Brown beef with garlic in batches; pour off drippings.
Return beef to pan; season with pepper. Stir in broth and thyme; bring to a boil. Reduce heat; cover tightly and simmer 1¾ to 2 hours or until beef is fork-tender.
Meanwhile heat oven to 425 degrees F. Line a jelly roll pan with foil and coat foil with sooking spray. Place mushrooms, tomatoes and onions in prepared pan. Drizzle with remaining oil and 2 1/2 tablespoons vinegar; toss.
Roast oven 20 to 25 minutes or until tender.
Combine cornstarch and water and stir into beef. Bring to a boil, stirring constantly, and cook 1 minute.
Stir in vegetables and remaining vinegar. Serve over hot couscous.