Preheat the oven to 410 degrees Fahrenheit (210 degrees Celsius).
Cut up the cauliflower into small florets. Cut the pumpkin into ½ inch thick wedges and then in half. You don’t need to peel the pumpkin.
Toss the cut up veggies with 1.5 tablespoon olive oil, salt and pepper to coat. Pour onto a large baking sheet and roast for about 40 minutes or until soft and lightly charred.
(Optional) Reserve some roasted cauliflower for garnish.
In the meantime, heat the remaining oil in a Dutch oven or a large pot with a thick bottom. Add diced onion and cook on medium heat stirring from time to time until softened, about 5-7 minutes.
Add the spices, garlic and ginger to the onion and cook, stirring another minute or two to toast the spices. If it’s starting to brown, add a splash of water.
Add broth and bring to boil.
Once the pumpkin and cauliflower are roasted, add them to the Dutch oven and remove from the stove.
Blend until smooth with an immersion blender or a standup blender (See note below).
Turn the stove back on. Stir in coconut milk and bring to a gentle simmer. Add 1 teaspoon apple cider vinegar and stir. Give the soup a taste. It will likely need more salt and pepper. If desired, add another teaspoon of vinegar for a little more acidity.
Serve hot with topped with reserved roasted cauliflower florets, pepitas and red pepper flakes, or your favorite toppings.