Fruit for garnish: dragon fruit, kiwi, star fruit
For syrup, chop lemongrass and heat with sugar and water until sugar has dissolved.
Let cool, then strain out lemongrass and chill syrup.
For frappes, pulse half of fruit with half the sugar syrup, 1 cup of ice cubes and 1 1/4 cups cream until blended and frothy. Pour into a chilled pitcher and repeat with remaining ingredients. Serve immediately.