Preheat your oven to 350°F (175°C). In a large Dutch oven, cook the bacon strips over medium heat until crispy, about 6-8 minutes. Remove and set aside, leaving the drippings in the pot.

Pat dry the beef chuck cubes and season with salt and pepper. Increase heat to medium-high and sear the beef in batches in the bacon fat for 4-5 minutes per side to create a crust. Remove and set aside.

Lower the heat to medium, add butter, then onions and carrots. Sauté for 5-6 minutes until softened, then add garlic and cook for another minute.

Mix in tomato paste and cook for 2-3 minutes, then add flour and stir for 1 minute until absorbed.

Deglaze the pot with burgundy wine, scraping up browned bits. Let simmer for 2-3 minutes, then add beef broth and bouillon base if using.

Return the beef and bacon to the pot, adding thyme and bay leaves. Simmer for 5 minutes.

Cover and transfer to the oven. Braise for 2.5 hours.

While the stew is cooking, sauté mushrooms and pearl onions in another skillet with melted butter until golden brown, about 5-7 minutes.

After 2.5 hours, stir in sautéed mushrooms and pearl onions. Cover and return to the oven for another 45-60 minutes.

Let the stew rest for 30 minutes before serving.