Heat olive oil in a large pot over medium-high heat.
Add beef stew meat, season with salt and pepper, and brown on all sides (about 5-7 min). Remove and set aside.
In the same pot, add onions and garlic. Sauté for 2-3 minutes until fragrant.
Stir in carrots, celery, and potatoes. Cook for 5 minutes.
Return beef to the pot. Add green beans, diced tomatoes, beef broth, water, bay leaves, and thyme.
Bring to a boil, then reduce heat to low. Cover and simmer for 1 to 1.5 hours, until beef is tender.
Stir in peas (if using) and cook for 5 more minutes.
Discard bay leaves. Adjust seasoning with salt and pepper.
Ladle into bowls and garnish with fresh parsley.