Curried Pumpkin Soup

Why I Love This Recipe
Ingredients You'll Need
2 medium onions, finely chopped (2 cups)
2 tablespoons unsalted butter
2 large garlic cloves, minced
1 1/2 tablespoons minced peeled fresh ginger
2 teaspoons ground cumin
1 teaspoon ground coriander
1/8 teaspoon ground cardamom
1 1/2 teaspoons salt
3/4 teaspoon hot red pepper flakes
2 (15 ounce) cans solid-pack pumpkin (3 1/2 cups, not pie filling)
7 cups water
1 1/2 cups reduced-sodium chicken broth (12 fl oz)
1 (14 ounce) can unsweetened coconut milk (not low-fat)
1/4 cup olive oil
2 teaspoons brown mustard seeds
8 fresh curry leaves
Directions
1. Cook onions in butter in a wide 6-quart heavy pot over moderately low heat, stirring occasionally, until softened, 3 to 5 minutes.
2. Add garlic and ginger and cook, stirring, 1 minute.
3. Add cumin, coriander, and cardamom and cook, stirring, 1 minute.
4. Stir in salt, red pepper flakes, pumpkin, water, broth, and coconut milk and simmer, uncovered, stirring occasionally, 30 minutes.
5. Purée soup in batches in a blender until smooth (use caution when blending hot liquids), transferring to a large bowl, and return soup to pot.
6. Keep soup warm over low heat.
7. Heat oil in a small heavy skillet over moderately high heat until hot but not smoking, then cook mustard seeds until they begin to pop, about 15 seconds.
8. Add curry leaves and cook 5 seconds, then pour mixture into pumpkin soup.
9. Stir until combined well and season soup with salt.
10. Soup can be thinned with additional water.
Can be made day ahead.