1 tsp coriander seeds

1/2 tsp black or yellow mustard seeds

3 tbsp vegetable oil

1 tsp curry powder

1 1/2 tbsp minced fresh ginger

1 large leek or 2 medium leeks, white parts chopped

1 1/2 pounds carrots, peeled and thinly sliced

grated lime peel from one lime

5 cups vegetable stock

juice from 1 lime

plain yogurt (garnish)

Grind coriander and mustard seeds in a spice mill. Heat oil in a large, heavy pot over medium-high heat. Add ground spices and curry powder; stir 1 minute. Add ginger and stir one minute. Add leeks, carrots and lime peel and saute until leeks begin to soften. Add the vegetable stock; bring to a boil then reduce the heat and allow the soup to simmer uncovered until carrots are tender, about 30 minutes. Cool slightly.

Working in batches, puree soup in blender until smooth. Return to pot and add more stock if too thick. Stir in lime juice; season with salt and pepper.  (Can be made a day ahead and refrigerated.)

Ladle hot soup into bowls and garnish with yogurt and maybe a cilantro sprig.