In a large skillet or Dutch oven, sauté bacon in butter over medium heat until crisp and browned (about 3 minutes). Remove bacon with a slotted spoon and transfer to a slow cooker.
Pat beef dry with a paper towel and season with salt and pepper. Sear beef in the butter/bacon fat until browned on all sides. Transfer beef to the slow cooker. Add tomato paste, garlic, salt, pepper, thyme, bay leaf, paprika, onions, carrots, potatoes and mushrooms to the slow cooker.
Heat the same skillet or Dutch oven over medium heat and add wine and broth. Simmer for 3-5 minutes, then whisk in the flour until there are no lumps. Allow to reduce and thicken slightly, then pour the wine mixture into the slow cooker.
Give everything a good stir, cover, and cook on LOW heat for 8 hours or on HIGH for 4-6 hours (until beef is fall-apart tender). Remove bay leaf, season with salt and pepper (to taste), and serve!