Remove the shells from the pistachios and gently rub them with your fingers to remove as much of the skin around the nut. Place in a food processor and pulse until you have a fine ground.
In a large pot, over medium heat, saute the shallots and leek with oil for about 10 minutes until softened and translucent.
Add garlic, ginger and the spices and continue to saute for an additional 2 minutes.
Add the rice flour and mix until the flour has nicely coated the ingredients inside the pot.
Add the ground pistachios and the remaining ingredients and bring to a gentle boil.
Reduce the heat to low, cover the pot and cook for about 45 minutes.
The soup should have a velvety and creamy consistency. Taste for seasoning and adjust the flavors by adding more salt or citrus flavoring. (See note).
Pour the soup into a large serving bowl and garnish with barberries, chives and more pistachios.
Serve with flatbread.