Toss the beef cubes with the flour, salt, and pepper until evenly coated.
Heat the olive oil in a large skillet over medium-high heat. Add the beef and sear until browned on all sides, about 5 minutes. Transfer the beef to the slow cooker.
Pour the red wine into the same skillet and scrape up any browned bits. Simmer for 1 minute, then add the mixture to the slow cooker.
Add the beef broth, pearl onions, carrots, garlic, and thyme to the slow cooker. Stir gently to combine.
Cover and cook on low for 8 hours until the beef is tender and the gravy has thickened.
Taste and adjust salt and pepper if needed before serving.