Preheat your oven to 425º F.
Prepare a parchment-lined baking sheet and distribute your cauliflower florets over it in an even layer. Drizzle some olive oil over the florets and season them with salt and pepper. Roast them in the oven for 30 minutes without tossing them.
10 minutes before the cauliflower is done, heat 1 TBSP of oil in a Dutch oven or stock pot. Add the onions and sautée until they've softened and become translucent. Then add the garlic and spices; stir to coat. If you need to add extra oil because the pan is seeming dry, go ahead.
When the cauliflower is ready, add it to the pot along with the pumpkin purée. Give it a good stir, and then stir in the broth and coconut milk.
Bring everything to a simmer, then crank the heat down and simmer on low for 10-15 minutes.
To blend, carefully transfer the soup to a blender (you will do this in batches), and blend until smooth. If you prefer some texture to your soup, you could simply use an immersion blender and blend the soup right there in the pot until you get the texture you prefer!
Serve and garnish with croutons, pepitas, microgreens, a drizzle of cream, chili flakes, etc.