How to Make It
Warm oil in a large, heavy pot over medium heat. Add ground beef, garlic powder, salt and pepper and cook, stirring, until no pink remains, 4 to 5 minutes. Using a slotted spoon, remove beef.
Add onion and carrots to same pot. Season with salt and pepper and cook, stirring often, until just tender, about 10 minutes. Add mushrooms and cook, stirring, until they release their liquid, about 3 minutes.
Stir broth and 2 cups water into pot, scraping up browned bits. Add beef and barley. Raise heat to high; bring to a boil. Reduce heat to medium low, cover and simmer until barley is tender, about 50 minutes. Skim off fat, if desired. Taste and season with salt and pepper. Serve hot.