In a large pot or Dutch oven, heat a small amount of oil over medium-high heat. Add the beef pieces and sear until browned on all sides. Remove the beef and set aside.

In the same pot, add the carrots, celery, onion, and mushrooms. Cook for 5-7 minutes, stirring occasionally, until the vegetables are tender.

Add the minced garlic and cook for an additional minute until fragrant.

Return the beef to the pot. Add the beef base, water, and bay leaves. Bring to a boil, then reduce the heat and simmer for 1 hour.

Stir in the pearl barley, salt, and pepper. Continue to simmer for another 45 minutes to 1 hour, or until the barley is tender and the soup has thickened.

Remove the bay leaves before serving. Adjust seasoning with additional salt and pepper if needed.