In stockpot or Dutch oven with tight fitting lid, cook bacon over medium heat. Remove from pan when crispy; drain. Remove ½ of bacon drippings from pan; reserve.
Combine flour and thyme in a 1-gallon recloseable food storage bag; salt and pepper taste. Add in beef; seal bag. Shake to coat beef. Place pot back over heat and increase to medium-high. When hot, add ½ the beef and brown; remove from pan and repeat with remaining beef adding additional bacon drippings as needed. Set brown beef aside.
Add additional bacon drippings to pan as needed. Add in carrots, onions, celery, mushrooms and garlic; salt and pepper. Sauté 5 minutes. Add in wine; simmer 2 minutes.
Stir in beef broth, tomato paste, fresh thyme and bay leaf. Add beef and bacon back in. Bring to a boil; reduce heat to simmer. Cover tightly. Simmer, stirring occasionally, 2-2½ hours.
Serve over mashed potatoes, if desired.