Begin by heating the olive oil in a skillet over medium-high heat. Once hot, add the beef stew meat and cook until browned on all sides, about 5 minutes. Transfer the browned beef to the slow cooker to build flavor from the start.
In the same skillet, add chopped onions, carrots, and celery. Sauté for about 5 minutes until vegetables start to soften and onions become translucent, releasing a fragrant aroma.
Add the minced garlic to the skillet and cook for 30 seconds until fragrant, stirring constantly to prevent burning. Then, pour the vegetables and garlic over the browned beef in the slow cooker.
Sprinkle the dried thyme over the contents of the slow cooker, then add the rinsed barley. Place the bay leaves on top and pour in the beef broth, ensuring all ingredients are submerged enough to cook evenly.
Cover the slow cooker with the lid and set it to low. Let it simmer gently for about 8 hours until the beef is tender and barley is soft but still chewy. During cooking, aroma of herbs and beef will fill your kitchen.
Once done, remove and discard the bay leaves, then gently stir the soup to distribute the barley and beef evenly. Taste and season with salt and pepper as needed for flavor balance.
Ladle the hearty soup into bowls, revealing a thick, fragrant broth dotted with chewy barley and tender beef. Serve hot and enjoy the comforting flavors of this rustic dish.
