Heat olive oil in a large stock pot over medium-high heat. Add beef and season generously with salt and pepper. Brown evenly, about 8-10 minutes.
Add onion, carrots and celery and season again with salt and pepper. cook until onions become translucent, about 5 minutes.
Add stock, barley, and thyme and bring to a boil. Reduce heat to a slow simmer and cook, covered, until meat is tender about an hour.
Taste and add more salt and pepper if necessary. Remove thyme stems and serve with a sprinkling of herbs if desired.