Start by preheating your oven to 325°F (160°C). This recipe requires slow cooking to achieve tender and flavorful results.
In a large, oven-safe Dutch oven or heavy-bottomed pot, cook the chopped bacon over medium heat until crispy. Remove the bacon from the pot and set it aside, leaving the bacon grease in the pot.
In the same pot, add the diced onion, sliced carrots, and minced garlic. Sautee the vegetables until they start to soften, about 5 minutes.
Push the vegetables to one side of the pot and add the beef stew meat in a single layer. Brown the meat on all sides, working in batches if necessary. This step helps to develop the flavors and creates a nice crust on the meat.
Once the meat is browned, stir in the tomato paste and cook for another minute to coat the meat and vegetables evenly.
Pour in the red wine and beef broth, scraping the bottom of the pot to release any browned bits. These browned bits, also known as fond, add depth and richness to the sauce.
Add the bouquet garni, pearl onions, and quartered mushrooms to the pot. Season with salt and pepper to taste. Bring the mixture to a simmer.
Cover the pot with a lid and transfer it to the preheated oven. Allow the Beef Bourguignon to cook for 2 to 3 hours, or until the meat is tender and the flavors have melded together.
While the Beef Bourguignon is cooking, prepare the flour and butter mixture, also known as a beurre manié. In a small bowl, mix together the all-purpose flour and softened butter until well combined. This mixture will act as a thickening agent for the sauce later on.
Once the Beef Bourguignon has finished cooking, remove it from the oven and place it on the stovetop over low heat. Stir in the beurre manié, a spoonful at a time, until the sauce reaches your desired consistency. Cook for an additional 5 minutes to allow the sauce to thicken.
Serve the Beef Bourguignon hot, garnished with fresh parsley. This dish pairs well with crusty bread or creamy mashed potatoes to soak up the flavorful sauce.