Preheat your oven to 350°F (175°C). In a 5-quart Dutch oven over medium-low, cook bacon until browned and the fat has rendered. Remove bacon with a slotted spoon and set aside.

Season the beef chunks generously with salt and pepper. Increase heat to medium-high and sear in batches until browned on all sides. Remove and set aside.

Reduce heat to medium. Add 2 Tbsp of butter and sauté onions and carrots for 2–3 minutes. Add garlic for another minute. Mix in tomato paste and cook until darkened—about 2–3 minutes.

Sprinkle the flour over the vegetables and stir to combine. Cook 2–3 minutes, stirring constantly. Add wine and scrape browned bits from the bottom. Stir in beef stock and bouillon to bring to a simmer. Add beef, bacon, thyme, and bay leaves.

Cover and transfer to the oven. Bake for 2½ hours.

About halfway through cooking, melt remaining butter in a skillet over medium-high heat. Sauté mushrooms until browned, then add pearl onions and cook for 5 more minutes. Season with salt and pepper.

Remove Dutch oven from the oven and stir in the mushroom and onion mixture. Return to the oven and cook for 45–60 more minutes, until the beef is fall-apart tender.

Let it rest, covered, for 30 minutes. This helps the flavors settle and the sauce thicken beautifully.