Grape must pudding (Moustalevria / Palouzes)

This seasonal old fashioned autumn pudding is made with grape molasses, made from grape must that has been reduced to a syrupy consistency, not to be confused with pomegranate molasses which are much more sour!
You can buy Petimezi (Grape Molasses syrup) in Greece and Cyprus. I always bring a few bottles home with me. The grape molasses can also be found online or in Turkish shops in the UK.
Palouzes (in Cypriot) or Moustalevria (in Greek), is a pudding made with either fresh grape juice during autumn or with concentrated grape juice (Petimezi or Epsima in Cypriot) when no fresh juice is available.

Ingredients (makes 4-5 puddings):
1/4 litre (9 fl oz) bottle of Petimezi
600ml 1 pint) water
25g flour
25g cornflour dissolved in ¼ cup of cold water
1-2 tbsp Rosewater
1 tbsp honey (if needed)

Method:
Dissolve the cornflour in ¼ cup of water. Place grape must and water in a heavy saucepan, add to the mixture, along with the flour.
Place saucepan over a medium heat and keep whisking until it thickens to a creamy texture, around 5-10 minutes. Taste and add honey if needed, then mix in the rosewater.
Rinse the serving dishes with cold water and distribute the mixture into the bowls. Allow to cool a little and then sprinkle with walnuts, cinnamon or sesame seeds.
Place in the fridge for a few hours and serve cold or at room temperature.