Heat 1 tablespoon of olive oil in a large Dutch oven over medium-high heat. Season the beef stew meat with salt and pepper, then add it to the pot. Sear for about 5-7 minutes until browned, then set aside.

Reduce heat to medium and add another tablespoon of olive oil. Sauté diced onion, carrots, and celery for 5-7 minutes until softened and onion is translucent.

Add minced garlic and cook for 1 minute until fragrant. Stir in the diced tomatoes, dried thyme, and bay leaf. Deglaze the pot by scraping up brown bits.

Pour in the beef broth, return seared beef, and bring to a gentle boil. Reduce heat to low, cover, and simmer for 45 minutes.

Stir in rinsed barley, cover, and simmer for an additional 20-25 minutes. Check for tenderness of barley.

Just before serving, stir in frozen peas and cook for 2-3 minutes. Adjust seasoning with salt and pepper, and remove bay leaf.

Ladle soup into bowls and garnish with chopped parsley. Optionally add grated Parmesan or sour cream before serving.