01 - Heat vegetable oil in a large, heavy-based pot over medium-high heat. Add beef cubes in batches and brown evenly on all sides. Remove and set aside.
02 - Add chopped onion, diced carrots, and celery to the pot. Cook for 5 minutes until softened, stirring frequently. Add minced garlic and cook for an additional minute.
03 - Return browned beef to the pot. Sprinkle flour over the meat and vegetables, stirring thoroughly to coat evenly.
04 - Stir in tomato paste and cook for 1 minute. Pour in red wine if using, scraping the pot bottom to release browned bits.
05 - Pour in beef stock, then add dried thyme, Worcestershire sauce, and bay leaves. Season with salt and black pepper.
06 - Bring mixture to a gentle simmer, cover, and cook on low heat for 1 hour, stirring occasionally.
07 - Remove lid and simmer uncovered for 20 to 30 minutes until beef is tender and sauce has thickened.
08 - Stir in frozen peas and cook for 2 to 3 minutes. Remove bay leaves.
09 - Allow filling to cool completely before using in pies or pasties.