01 - Season beef cubes evenly with salt and freshly ground black pepper.
02 - Heat olive oil in a large skillet over medium-high heat. Brown beef in batches, approximately 3 to 4 minutes per batch, ensuring all sides are seared. Transfer browned beef to the slow cooker.
03 - Place carrots, potatoes, celery, chopped onion, and minced garlic into the slow cooker with the beef.
04 - In a mixing bowl, whisk together beef broth, tomato paste, Worcestershire sauce, and red wine if using. Pour mixture evenly over the beef and vegetables.
05 - Incorporate dried thyme, dried rosemary, and bay leaves into the slow cooker. Stir gently to combine ingredients.
06 - Cover and cook on low setting for 8 hours or on high for 4 to 5 hours, until beef and vegetables are tender.
07 - Thirty minutes before completion, mix cornstarch or gluten-free flour with water to create a slurry. Stir the slurry into the stew along with frozen peas. Cover and cook for an additional 30 minutes to allow thickening.
08 - Remove bay leaves before serving. Taste stew and adjust salt and pepper as needed.