You will need:
1 1/2 cups plain yogurt
1 tsp sugar
1 1/4 cups water
3 tbsp puréed fruit (mango or strawberry, usually)
crushed pistachio nuts (optional)
Place the yogurt in a jug and whisk it until it is frothy, about two minutes. Add the sugar. Mix in the water and fruit and whisk until blended. Serve chilled with pistachio nut garnish.
Frozen fruits are really good for this drink; find them in the dessert section of the freezer department.