Preheat oven 325 degrees. Prepare a baking pan with pan spray.
Brown roast on all sides in a skillet over medium-high heat.
Place roast in baking pan and coat well with the envelope of onion soup mix, garlic powder, black pepper, and bay leaf. Cut vegetables: carrots into 2-bite lengths, large mushrooms in fourths (or halves if small), onions cut into fourths, cabbage into large wedges, and celery cut into 2-inch lengths with leaves left on. Distribute the vegetables around the roast, to form an attractive and bountiful display.
Cover the roast with the can of soup and tomatoes and then cover with aluminum foil. Bake for 2 1/2 hours. Save the juice to make gravy.