In this vegan golden vegetable soup, butternut squash adds color, while ginger, serrano pepper and spices add depth and earthy flavors.
Heat oil in a large Dutch oven or heavy stockpot over medium heat. Add onion and squash; cook, stirring often, until the onion is translucent, about 7 minutes. Add serrano and ginger; cook, stirring often, until fragrant, about 1 minute.
Reduce heat to medium-low and add coriander, cumin, turmeric and 1/4 teaspoon fennel seeds. Cook, stirring constantly, until fragrant, about 1 minute. Stir in cauliflower and broth. Bring to a boil over medium-high heat; reduce heat to medium-low, and simmer, stirring occasionally, until the squash is fork-tender, 25 to 30 minutes.
Working in 2 batches, transfer the squash mixture to a blender. Secure the lid on the blender and remove the center piece to allow steam to escape. Place a clean towel over the opening. Process until smooth, about 1 minute. (Use caution when pureeing hot liquids.) Return the mixture to the pot.
Stir 1 cup coconut milk into the soup. Bring to a gentle simmer over medium-low heat. Stir in lime juice and salt. Remove from heat.
Divide the soup among 4 bowls. Top each with 1 tablespoon coconut milk and a pinch of fennel seeds.
Cover and refrigerate for up to 3 days or freeze for up to 6 months.