
In a large bowl, toss the beef cubes with flour, salt, and pepper until evenly coated.
In a large Dutch oven or pot, cook the bacon over medium heat until crisp. Remove the bacon and set aside, leaving the rendered fat in the pot.
Brown the beef in batches in the bacon fat, ensuring not to overcrowd the pot. Remove the beef and set aside.
Add the onion and carrots to the pot and cook until softened, about 5-7 minutes. Stir in the garlic and cook for another minute until fragrant.
Pour in the red wine and beef broth, scraping up any browned bits from the bottom of the pot. Add the tomato paste, thyme, and bay leaf.
Return the beef and bacon to the pot. Bring to a simmer, then cover and transfer to a preheated oven at 325°F (160°C) for 2.5-3 hours, or until the beef is very tender.
In the last 30 minutes of cooking, sauté the mushrooms in butter in a separate pan until browned. Add the mushrooms to the stew and continue cooking until the stew has thickened.
Remove the bay leaf and thyme sprigs before serving. Garnish with fresh parsley.