For the semolina, bring the milk and cream with the salt and vanilla sugar to the boil. Stir in the semolina well, bring to the boil and remove the pot from the stove. Let the semolina swell for 10 minutes. Set the porridge aside and stir frequently.
For the blackberry sauce, wash and sort the blackberries, place in a blender with powdered sugar and lemon juice and puree. Put the pureed berries through a fine sieve and pour into a jug.
Arrange the semolina on dessert plates or in glasses, pour in the sauce and decorate with blackberries if necessary.