Pistachio Soup - cooking recipe

Ingredients

3/4 cup unsalted shelled pistachio (4 oz, not dyed red)
2 cups reduced-sodium chicken broth (16 fl. Oz)
1 medium leek (white and pale green parts only)
1/4 cup finely chopped onion
1 garlic clove, finely chopped
1/4 teaspoon finely grated peeled fresh ginger
1/8 teaspoon cayenne
1 1/2 tablespoons vegetable oil
1 tablespoon cumin seed
1/2 teaspoon coriander seed
2 cups water
3/4 teaspoon salt
1/2 teaspoon black pepper
1/8 teaspoon turmeric
2 tablespoons rice flour
2 tablespoons dried barberries (aka \"zereshk\"... you can substitute cranberries soaked first in hot water)
1/2 teaspoon grape juice concentrate (grape molasses) or 1/2 teaspoon grape jelly
6 tablespoons fresh orange juice
2 tablespoons fresh lime juice

Preparation

Cook shelled pistachios in a small saucepan of boiling water 1 minute, then drain and rub off skins.
Transfer 1/2 cup skinned pistachios to a blander (reserve remainder), then add broth and blend until smooth, 1 to 2 minutes.
Chop leek and wash in a bowl of cold water, agitating it, then lift out with a slotted spoon and transfer to a bowl along with onion, garlic, ginger and cayenne.
Heat 2 T oil in a 3-4 quart heavy saucepan over moderately high heat until just beginning to smoke, then cook cumin and coriander seeds, stirring, until fragrant and a shade or two darker, 10 to 30 seconds. Stir in leek mixture, then reduce heat to moderately low and cook, covered, stirring occasionally, until vegetables are softened, about 5 minutes.
Add pistachio puree, water, salt, pepper, and turmeric, then whisk in rice flour and bring to a boil, whisking constantly. Reduce heat to low and gently simmer, covered, whisking occasionally, 30 minutes.
Meanwhile, heat remaining 1/2 T oil in a 7-8\" heavy skillet over moderate heat until hot but not smoking, then cook barberries, grape molasses, and remaining 1/4 c skinned pistachios, stirring, until combined and heated through, 30 seconds to 1 minute. (be careful not to burn barberries) Transfer to a small bowl.
Puree soup in 2 or 3 small batches in blender (use caution when blending hot liquids) until smooth, transferring to a large bowl.
Return soup to pot, then stir in juice and bring to a simmer. Season with salt and pepper. Serve soup topped with pistachio mixture.
Cooks' note: Soup, without citrus juice, can be made 1 day ahead and cooled, uncovered, then chilled, covered. Reheat, stirring in juice.
Pistachio topping can be made 1 day ahead and kept covered at room temperature.