In a large stockpot or Dutch oven, heat olive oil spray over medium heat.
Season diced sirloin steak with salt and pepper and add to pot. Stir occasionally until evenly browned, about 6 to 8 minutes.
Add 1 cup diced onion, 2 large peeled and diced carrots, 2 diced celery ribs. Stir occasionally, about 3 to 4 minutes.
Add 3 minced garlic cloves and 8 ounces sliced baby Bella mushrooms. Stir occasionally, about 3 to 4 minutes.
Sprinkle in 3 tablespoons flour. Mix well.
Add 2 tablespoons tomato paste, 1 teaspoons dried thyme leaves, and 2 bay leaves. Thoroughly combine.
Pour in ½ cup wine (scraping any browned bits from the bottom of the pot).
Stir in 3 cups beef stock. Bring to a boil and reduce heat.
Add 2 peeled and cut potatoes. Simmer for at least 50 minutes until beef and potatoes are tender.
Remove and discard bay leaves before serving.
Top with diced greens from baby Vidalia onions.