Preheat the oven to 425°. On a parchment-lined baking sheet, toss the cauliflower with 1 tablespoons of the oil and 1/2 teaspoon salt. Arrange in an even layer. On a second sheet pan, toss the sweet potato with 1 tablespoon oil and 1/2 teaspoon salt. Roast in the oven for 30 minutes, or until the vegetables are tender and caramelized, switching the pans from top to bottom halfway through.

Meanwhile, heat 1 tablespoon oil in a large stockpot or Dutch oven. Saute the onion over medium-high heat until soft, 5 minutes. Stir in the garlic and curry paste. Cook until very fragrant, 2 minutes. Pour in the coconut oil and 2 cups water and scrape up any brown bits that may have formed on the bottom of the pan. Bring to a boil.

Stir in the roasted cauliflower, sweet potato, maple syrup (if using) and lime juice. Bring back to a simmer then remove from the heat. Puree using an immersion or standing blender until very smooth, adding more liquid as necessary to create the consistency you want. Taste for seasoning and add more curry or salt as necessary.

Ladle the soup into bowls and garnish with the avocado and hemp seeds, if using.