Curried Pumpkin Soup
2 onions, finely chopped
2 tablespoons butter
2 garlic cloves, minced
1 1/2 tablespoons ginger, minced
2 teaspoons ground cumin
1 teaspoon ground coriander
1/8 teaspoon ground cardamom
1 1/2 teaspoons salt
1/4 teaspoon dried red pepper flakes
2 cans (15-ounce each) solid-pack pumpkin, not pie filling
7 cups water
1 1/2 cups chicken broth
14 ounces unsweetened coconut milk
1/4 cup olive oil
2 teaspoons brown mustard seeds
8 fresh curry leaves
Cook onions in butter in a 6-quart wide heavy pot over medium-low heat, stirring occasionally, until softened, 3-5 minutes. Add garlic and ginger and cook, stirring 1 minute. Add cumin, coriander, and cardamom and cook, stirring 1 minute. Stir in salt, red pepper flakes, pumpkin, water, broth, and coconut milk and simmer, uncovered, stirring occasionally, 30 minutes. 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. Keep soup warm over low heat.
Heat oil in a small heavy skillet over medium-high heat until hot but not smoking, and then cook mustard seeds until they begin to pop, about 15 seconds. Add curry leaves and cook 5 seconds, then pour mix into pumpkin soup. Stir until well combined, then season with salt. Thin with additional water if desired.
Soup can be made one day ahead and cooled completely, uncovered, then chilled, covered.