Place the spinach in a colander and squeeze out the excess water. Chop the spinach very finely.
Transfer to a food processor with the garlic, curry powder, ginger and buttermilk. Season well and stir in the chopped mint. Add the measured water and process the mixture until smooth.
Ladle the soup into chilled bowls, drop 2 ice cubes into each bowl and garnish with a few extra mint leaves. Serve immediately.