Cook the bacon in a large Dutch oven over medium heat until crisp. Remove the bacon with a slotted spoon and set it aside, leaving the fat in the pot.
Season the beef cubes with salt and pepper. Brown the beef in the bacon fat in batches until all sides are seared. Transfer the browned beef to a plate.
Add the onion, carrots, and mushrooms to the pot. Cook for 5 minutes until the onion softens. Stir in the garlic and cook for 1 minute more.
Sprinkle the flour over the vegetables and stir for 1 minute. Add the tomato paste and mix until everything is coated.
Pour in the red wine and scrape the bottom of the pot to release any browned bits. Add the beef broth, thyme, bay leaf, and the reserved bacon and beef.
Bring the mixture to a simmer, then cover and cook on low heat for 2 hours until the beef is fork-tender. Remove the bay leaf before serving and sprinkle with parsley.