1. Cut beef into bite-sized chunks and dip in seasoned flour. Shake off excess and reserve the beef.
2. Heat 2 tbsp oil in a pan and gently fry onions and garlic over gentle heatuntil softened but not brown. Transfer to a flameproof casserole.
3. Add remaining oil to pan and fry beef in batches to brown on all sides. Add to casserole. Pour over beef stock and red wine and bring to bubbling. Season with salt and freshly ground black pepper. Turn down to simmer for 1 1/2 hours with the lid half on, or until beef is tender.
4. At the same time roll out the pastry slightly thinner. Cut out 4 shamrocks using plain pastry cutters for the leaves and a thin strip for the stalk.
5. Place on a greased baking sheet. Brush with beaten egg then bake at Gas 6/400F/200C for 10 minutes until golden and crisp.
6. When beef is tender tuck in oysters and add any juice in the shells andcook 5 minutes more. Serve beef and oysters in bowls, scattered with parsley and topped with pastry shamrock.