Bring the milk to the boil in a pan with the salt and vanilla. Stir in the semolina, simmer for approx. 5 mins. over a very low heat, stirring constantly to form a thick paste. Remove the pan from the heat, cover and allow to absorb for approx. 10 mins. Remove the vanilla pod. Stir in the sugar, whipped cream and lemon zest. Spoon the mixture into the prepared moulds, level off and leave to cool. Cover the semolina puddings and chill for approx. 3 hrs.