Preheat the oven to 425 degrees F. Line a sheet pan with parchment paper.
Slice the the squash in half and scoop out the seeds. After that, cut the squash into wedges about 1 to 2 inches wide.
Toss the squash with 1 tablespoon olive oil, 1/2 teaspoon kosher salt and 1/4 teaspoon black pepper. Arrange them in a single layer on the baking sheet.
Roast the squash until it is tender, about 30-35 minutes.
When the squash is cool enough to handle, use a spoon to scoop out the flesh, discarding the skin.
Heat the olive oil in a large saucepan or dutch oven over medium high heat. Add the onions and sauté for 5 minutes until they start to soften.
Stir in the garlic, ginger, cumin, turmeric, 1/2 teaspoon kosher salt and 1/4 teaspoon black pepper. Continue cooking for 1 minute until everything is fragrant.
Add the roasted squash flesh, vegetable broth, and coconut milk (reserving 1/4 cup). Simmer for 12-15 minutes until the soup thickens and reduces slightly.
Use an immersion blender to puree until smooth or transfer it to a blender in batches. Squeeze in the lime juice.
Divide the soup into bowls. Drizzle with the reserved coconut milk and sprinkle with chopped herbs and black pepper.