A rich hearty stew filled with big chunks of veggies and tender beef.
Add flour, salt, pepper, and garlic powder to a shallow dish. Dredge meat into the flour mixture and shake off excess. Place 2 tbs of the olive oil in a frying pan. Brown meat over medium-high heat turning on all sides. (May need to do in batches so the meat does not steam instead of brown.) Set browned meat on a paper towel-lined plate. Place an additional 1 tbs olive oil and butter into a frying pan. Add mushrooms and onion. Saute for 3-4 minutes. Pour mushrooms and onions into the bottom of a slow cooker insert. Add meat, broth, diced tomatoes, potatoes, carrots, celery, thyme and bay leaves. Stir until all combined. Cook on low for 6-8 hours or high for 4-5 hours. 30 minutes before serving. Whisk together cornstarch and water to make a slurry. Pour into the stew and stir well.