In a large bowl, combine the beef cubes, olive oil, salt, black pepper, garlic powder, and onion powder. Toss until the beef is evenly coated.
In a large skillet over medium-high heat, brown the beef in batches for about 5 minutes, transferring it to the slow cooker as it browns.
Add the carrots, potatoes, celery, onion, beef broth, Worcestershire sauce, thyme, and bay leaf to the slow cooker. Stir to combine.
Cover and cook on low for 7 to 8 hours or on high for 4 to 5 hours, until the beef is tender.
If using, stir in the frozen peas during the last 30 minutes of cooking.
Remove the bay leaf before serving. Adjust seasoning if necessary.