To make the stock, brown the marrow bones in a roasting pan in a preheated oven, 200°C/400°F (gas mark 6), for about 30 minutes. Put the bones in a large pan together with the peppercorns, anise, whole cloves, onions, ginger, radish and water. Bring to the boil. Reduce the heat, cover and simmer for 2-3 hours, skimming off any fat or scum from the surface from time to time. Cool, then strain.
Cook the rice noodles in boiling water for 3-5 minutes. Drain and put into large individual soup bowls. Add some beef, spring onions, chillies and beansprouts to each bowl. Bring the stock to a fast rolling boil and pour it into the soup bowls. Add the egg yolk and mint leaves to each bowl.
Serve at once sprinkled with a garnish of your choice and add fish sauce etc., according to taste.
© 1994 Keith Floyd estate. All rights reserved.