Pat the beef cubes completely dry with paper towels. Season generously on all sides with salt and pepper. Heat 1 tablespoon of olive oil in a large skillet over medium-high heat until shimmering. Working in batches, add the beef cubes in a single layer and sear for 3-4 minutes per side until deeply browned. Transfer the browned beef to your slow cooker.

Add the remaining tablespoon of olive oil to the same skillet over medium heat. Add the diced onion and cook for 5-7 minutes until softened. Add the minced garlic and cook for another minute. Stir in the tomato paste and cook for 2 minutes. Pour in about ½ cup of the red wine to deglaze the pan, scraping up browned bits. Let it simmer for 2 minutes before transferring to the slow cooker.

Add the remaining red wine, beef broth, Worcestershire sauce, bay leaves, and dried thyme to the slow cooker. Stir to combine. Cover and cook on LOW for 6-7 hours or on HIGH for 3-4 hours. About 1 hour before cooking time is complete, add the carrot chunks, potato chunks, and frozen pearl onions.

Once the vegetables are tender, whisk the flour with ½ cup of the hot stew liquid until smooth. Slowly pour this back into the slow cooker while stirring. Cover and continue cooking on HIGH for another 30-45 minutes until thickened.

Turn off the slow cooker and remove the bay leaves. Stir in the chopped fresh parsley and adjust seasoning with salt and pepper if needed. Let the stew rest for 10-15 minutes before serving.