Warm 1 tablespoon of olive oil in a large skillet over medium heat. Add the chopped bacon and cook, stirring often, until the bacon is crisp and has rendered its fat, about 6–8 minutes. Transfer the bacon with a slotted spoon to a plate lined with paper towels and set aside, leaving the bacon drippings in the skillet.

Pat the beef chuck cubes dry with paper towels, then season them evenly with the salt and black pepper. Sprinkle the all-purpose flour over the seasoned beef and toss until all the pieces are lightly coated.

Add another 1 tablespoon of olive oil to the skillet with the bacon drippings and increase the heat to medium-high. Brown the beef in batches, turning the pieces so they develop a deep brown crust on several sides, about 3–4 minutes per batch. Do not overcrowd the pan, and add the remaining 1 tablespoon olive oil if the skillet becomes dry. As each batch browns, transfer the beef to the slow cooker.

Reduce the skillet heat to medium. Add the chopped yellow onion and sliced carrots to the pan. Cook, stirring and scraping up the browned bits from the bottom, until the onion softens slightly, about 4–5 minutes.

Stir the minced garlic and tomato paste into the onion and carrot mixture. Cook for 1 minute, stirring constantly, until the garlic is fragrant and the tomato paste darkens slightly in color.

Pour in the dry red wine and beef broth, then add the Worcestershire sauce. Stir well to combine, scraping up any remaining browned bits from the bottom of the skillet. Bring this mixture just to a simmer, then remove from the heat.

Place the browned beef cubes and the cooked bacon into the slow cooker if they are not already inside. Add the dried thyme and bay leaves on top of the meat.

Carefully pour the warm wine and broth mixture with the onions, carrots, garlic, and tomato paste over the beef and bacon in the slow cooker, ensuring the meat is mostly submerged in the liquid.

Cover the slow cooker with its lid and cook on LOW for 8 hours, or until the beef is very tender and breaks apart easily with a fork.

About 1 hour before the end of cooking, stir in the halved cremini mushrooms, making sure they are pushed down into the sauce. Replace the lid and continue cooking on LOW for the remaining time.

When the cooking time is complete, remove the bay leaves from the slow cooker and discard them. Taste the sauce and adjust seasoning with a little extra salt or black pepper if needed.

Sprinkle the chopped fresh parsley over the beef bourguignon just before serving, and gently stir once or twice to distribute the herbs through the stew.