01 - Heat a large skillet over medium-high heat and brown the beef cubes in batches until browned on all sides. Transfer to the slow cooker.
02 - Place potatoes, carrots, celery, onion, and garlic into the slow cooker with the beef.
03 - Whisk together beef broth, red wine if using, tomato paste, and Worcestershire sauce, then pour over meat and vegetables.
04 - Add salt, pepper, thyme, rosemary, and bay leaves, stirring gently to combine.
05 - Cover and cook on low for 8 hours until beef and vegetables are tender.
06 - Mix cornstarch and water until smooth and stir into the slow cooker.
07 - Add frozen peas, cover, and cook on high for 20 to 30 minutes until stew thickens.
08 - Remove bay leaves, adjust seasoning as needed, and serve hot.