Bring to the boil, stirring until thickened, then add the Worcestershire sauce and sugar and season, to taste, with salt and freshly ground ... the beef casserole. Serve with mashed potatoes ...
For the casserole ... or until the beef is very tender. Add the chestnuts and cook for a further 30 minutes. Meanwhile, for the leek colcannon, cook the potatoes in a pan of simmering water ...
Mix the mustard, horseradish and double cream (if using) in a bowl until well combined. Just before serving, stir it into the beef casserole. Serve with mashed potatoes and steamed vegetables.