1. Blend the cornflour to a smooth paste with 30 ml (2 tbsp) of the milk.
2. Boil the remaining milk with the lemon rind and strain it on to the blended mixture, stirring well.
3. Return the mixture to the pan and bring to the boil, stirring all the time, until the mixture thickens and cook for a further 3 minutes. Add sugar to taste.
4. Pour into a 600 ml (1 pint) dampened jelly mould and leave for several hours until set. Turn out to serve with fresh fruit