Rachel Allen shows how to make a wonderfully rich gnocchi with gorgonzola cream, walnuts and rocket. She meets Michelin-starred chef Jason Atherton to find out what's  on the menu - not at his renowned restaurant, Maze, but at home. Rachel teaches her cookery school family how to make a tasty chicken casserole with cheesy herb dumplings. This hearty one-pot dish will become a firm family favourite. (A-C)