Put the sago, milk and salt in a saucepan and bring to the boil while stirring. Let it simmer gently for 2 minutes on the lowest possible heat.
Beat the eggs with the sugar and SLOWLY stir in a little of the warm sago mass to equalize the temperature of both masses. Avoid lumps in the process. Then slowly pour the egg mixture into the saucepan and cook for 3 minutes on the lowest setting, stirring constantly. When everything has cooled down a bit, carefully stir in the vanilla flavor.