
Preheat oven to 325°F (160°C). In a large Dutch oven or oven-safe pot, cook bacon over medium heat until crisp. Remove bacon and set aside, reserving the rendered fat in the pot.
Season beef cubes with salt and pepper. In batches, brown the beef in the bacon fat over medium-high heat. Remove beef and set aside.
Add chopped onion and carrots to the pot and cook until softened, about 5-7 minutes. Add minced garlic and cook for another minute until fragrant.
Stir in tomato paste and cook for 1-2 minutes. Pour in red wine, scraping up any browned bits from the bottom of the pot. Bring to a simmer.
Return beef and bacon to the pot. Add beef broth, thyme, and bay leaf. Bring to a simmer, then cover and transfer to the preheated oven.
Braise in the oven for 2.5-3 hours, or until beef is very tender. In the last 30 minutes of cooking, add sliced mushrooms to the pot.
Remove bay leaf and thyme sprigs before serving. Garnish with fresh parsley, if desired. Serve hot with mashed potatoes or crusty bread.