Preheat your oven to 350°F (175°C).

In a large Dutch oven, cook bacon strips over medium-high heat until crispy, about 5-7 minutes. Transfer bacon to a plate, leaving fat in the pot.

Pat beef chuck cubes dry, season with salt and pepper, and sear in the bacon fat for 3-4 minutes on each side. Remove and set aside.

Add butter, onions, and carrots to the pot and sauté for 5-6 minutes until soft. Stir in garlic and tomato paste, and cook for another 2-3 minutes.

Sprinkle flour over the vegetables, stir for 2-3 minutes until the raw taste cooks out.

Pour in the red wine, deglaze by scraping up browned bits, and allow to simmer for 5 minutes. Stir in beef broth and bouillon base.

Return seared beef and bacon to the pot, add thyme and bay leaves, stir, and bring to a gentle simmer.

Cover the pot and transfer to the oven to braise for 2.5 hours.

Stir in cremini mushrooms and pearl onions. Cover and return to oven for another 45-60 minutes.

Once cooked, let the stew rest for 30 minutes before serving with mashed potatoes or French bread.