In a large skillet over medium heat, add the chopped bacon and cook until crispy. Remove the bacon and set aside, leaving the drippings in the pan.
Increase the heat to medium-high and add olive oil to the skillet. Once heated, add the beef cubes in batches, browning them on all sides. Transfer the browned beef to the slow cooker.
In the same skillet, add the diced onion and minced garlic. Sauté for about 3-4 minutes or until the onions are translucent.
Add the sautéed onions and garlic to the slow cooker with the beef. Then, add the sliced carrots, quartered mushrooms, crispy bacon, red wine, beef broth, tomato paste, dry thyme, bay leaves, salt, and pepper.
Stir everything together to combine, ensuring the beef and vegetables are evenly distributed in the liquid.
Cover the slow cooker with the lid. If using the low setting, cook for 8 hours. If using the high setting, cook for 4 hours.
Once cooking time is complete, remove the bay leaves. Taste and adjust seasoning if necessary. If desired, garnish with fresh parsley before serving.
For a thicker sauce, you can mix a tablespoon of cornstarch with two tablespoons of water and stir it into the stew during the last 30 minutes of cooking.
Serve over mashed potatoes, egg noodles, or crusty bread to soak up the delicious sauce.