For the raita: Place the cucumber and tomatoes
in a sieve
for about 15 minutes, to drain
off any excess liquid. Add to a bowl with the yogurt and buttermilk and stir well to combine. Season with salt.
For the soup: Put the coriander and cumin seeds into a small skillet and toast over low heat until they just begin to smoke and are very fragrant, about 15 seconds. Grind in a mortar and pestle
Put the raita
into a large glass bowl and whisk
in the toasted spices
, vegetable broth
and salt. Place in the fridge until completely chilled, about 2 hours. Ladle the soup into bowls and garnish
with a pinch of paprika and chopped fresh mint.