In a large skillet, cook bacon over medium heat until crisp. Place bacon in the bottom of a slow cooker.
Add chopped onions to the skillet and cook until soft and translucent, about 5 minutes.
Season cubed, chuck steak with salt and pepper.
Add seasoned beef to the skillet, and sear on all sides for about 2-3 minutes.
Add seared beef cubes to the slow cooker with the cooked bacon and onions.
Carefully pour red wine into the skillet, scraping up all the browned bits in the pan. Allow the wine to come to a simmer. Simmer on low to reduce, about 3-4 minutes.
Slowly add chicken broth, tomato sauce and soy sauce to the skillet and bring to a low simmer.
Whisk in the flour. Once flour lumps are gone add the sauce to the slow cooker.
Add thyme, garlic, carrots, potatoes, sliced mushrooms to the slow cooker and give it all a good stir.
Cover and cook on low until beef is tender; 8-10 hours.
Serve with a loaf of crusty french bread to soak up all the juices on your plate.