Pour all the ingredients cold into a saucepan and whisk until the sugar and starch have completely dissolved.
Bring to the boil while stirring until the mixture thickens and starts to bubble. Then continue to heat for 1 minute while stirring and then transfer to dessert glasses. Allow to cool completely.
Strawberry-rhubarb compote
Peel the rhubarb.
Chop the strawberries and rhubarb and simmer with the sugar and rose water in a saucepan over medium heat for about 10 minutes. Stir and leave to cool.
Top the muhalabia with compote and pistachios and serve.