Pat the beef cubes completely dry with paper towels and season generously with salt and pepper. This is crucial for getting a good sear.

In a large Dutch oven over medium heat, cook the bacon until crisp, about 8-10 minutes. Using a slotted spoon, transfer the bacon to a plate, leaving the rendered fat in the pot.

Increase the heat to medium-high. Working in batches to avoid overcrowding, sear the beef cubes in the bacon fat on all sides until deeply browned. This can take 3-5 minutes per batch. Transfer the seared beef to the plate with the bacon. Add a tablespoon of olive oil if the pot becomes too dry.

Reduce heat to medium. Add the chopped onion and sliced carrots to the pot and cook, stirring occasionally, until softened, about 5-7 minutes. Add the minced garlic and tomato paste and cook for another minute until fragrant, stirring constantly.

Sprinkle the flour over the vegetables and cook, stirring, for 1 minute to cook out the raw flour taste. Slowly pour in the red wine, scraping the bottom of the pot with a wooden spoon to release all the flavorful browned bits (the fond).

Bring the wine to a simmer and let it cook for about 5 minutes, allowing it to reduce slightly. Return the seared beef and cooked bacon (along with any accumulated juices) to the pot. Add enough warmed beef broth to just cover the meat. Stir in the thyme sprigs and bay leaves.

Preheat your oven to 325°F (165°C). Bring the stew to a gentle simmer on the stovetop. Once simmering, cover the Dutch oven with its lid and transfer it to the preheated oven.

Braise for 2.5 to 3 hours, or until the beef is exceptionally tender and easily falls apart with a fork.

About 30 minutes before the beef is done, prepare the garnish. In a large skillet, melt 2 tablespoons of butter over medium heat. Add the peeled pearl onions and cook, stirring occasionally, until they are lightly browned and tender, about 10-15 minutes.

Add the mushrooms to the skillet with the onions. Cook until the mushrooms have released their liquid and are nicely browned, about 8-10 minutes. Season with a pinch of salt and pepper. Set aside.

Carefully remove the Dutch oven from the oven. Discard the thyme sprigs and bay leaves. Skim any excess fat from the surface of the stew if desired.

Gently stir the cooked pearl onions and mushrooms into the stew. Taste and adjust seasoning with more salt and pepper if needed. Let the stew rest for 10-15 minutes to allow the flavors to meld.

Serve hot, garnished with fresh chopped parsley. This French Beef Bourguignon is traditionally served with mashed potatoes, creamy polenta, egg noodles, or crusty bread for sopping up the delicious sauce.