- 3 tablespoons plus 1 teaspoon vegetable oil
- 2 1/2 cups chopped onions
- 8 cups 1-inch pieces peeled acorn squash (about 3 1/4 pounds)
- 2 tablespoons chopped fresh ginger
- 4 1/2 cups (or more) canned low-salt chicken broth
- 2 tablespoons tomato purée
- Pinch of cayenne pepper
- 1 tablespoon cumin seeds
- 1 tablespoon mustard seeds
- Heat 3 tablespoons oil in heavy large pot over medium-high heat. Add onions; sauté until light golden, about 8 minutes. Add squash and ginger; sauté 5 minutes. Add 4 1/2 cups broth. Simmer until squash is very tender, about 35 minutes.
- Working in batches, purée soup in blender. Return to same pot. Add tomato purée and cayenne. Season to taste with salt and pepper. Simmer 10 minutes to blend flavors; add more broth if soup is too thick. (Can be prepared 1 day ahead. Cover and refrigerate. Rewarm soup over medium heat before serving.)
- Heat 1 teaspoon oil in small skillet over medium heat. Add cumin and mustard seeds and stir until fragrant, about 2 minutes. Ladle soup into bowls. Top with seed mixture and serve.