Combine mangoes and water in a medium pot. Simmer until a spoon pressed into the mango's surface makes a dent, about 30 minutes. Remove from pot. Cool. Remove skin and seed and mash the flesh in a heavy based saucepan. Heat pulp over medium heat while stirring, about 5 minutes. Add sugar, saffron and cardamom and stir until sugar has dissolved, another five minutes. Taste mixture and add more sugar if necessary. Remove from heat and cool in. Transfer to a sealed container and refrigerate until ready to use. To serve, put 2 tablespoons of mixture to a glass and top with ice cold water . Stir well.
