Season the beef cubes with flour, salt, and pepper in a large bowl. Toss to coat evenly.
Heat olive oil in a skillet over medium-high heat. Brown the seasoned beef on all sides until seared, about 3–4 minutes per side. Transfer to the slow cooker.
Add chopped onion, garlic, carrots, and celery to the slow cooker. Stir in beef broth, Worcestershire sauce, thyme, and bay leaves.
Cover and cook on low for 7–8 hours or on high for 4–5 hours, until the beef is tender.
About 30 minutes before serving, add cubed potatoes and continue cooking until potatoes are fork-tender.
Stir in frozen peas during the last 5 minutes of cooking. Remove bay leaves before serving.
Notes
Serve hot with crusty bread or over mashed potatoes for an extra comforting meal.