In a small bowl dissolve the cornstarch with the milk or water. Whisk to mix together.
Place mixture in a pot over medium heat and add the sugar and vanilla. Stir to combine, and then cook until the mixture coats the back of a wooden spoon. Remove from heat, and let cool a bit.
Prepare 2-3 ramekins and lightly grease the inside of the ramekins. Pour the mixture in the ramekins making sure to leave some space from the top. Chill the mahalepi covered for 6 hours or overnight.
Serve with the mango strawberry sauce, and top with sprinkled pistachios. You can get fancy and add the dried rose petals.