Cook the bacon in a skillet over medium heat until crisp. Remove the bacon and set it aside, leaving the drippings in the pan.
Season the beef cubes with salt and pepper. Brown them in the same skillet in batches until all sides are seared. Transfer the beef to the slow cooker.
Add the cooked bacon, red wine, beef broth, carrots, onion, mushrooms, garlic, tomato paste, flour, thyme, and bay leaves to the slow cooker. Stir to combine everything.
Cover and cook on low for 8 hours. The beef should be very tender and the sauce slightly thickened.
Remove the bay leaves. Taste and adjust salt and pepper if needed.
Slice the crusty bread and serve it alongside the stew.