Cook the rice according to package instructions or see instructions below.
Meanwhile (about halfway through cooking the rice), heat the olive oil in a large stockpot or dutch oven over medium-low heat. Add the carrots and saute for 5 minutes; then the onion for about 5 minutes more, and the celery for 3 minutes after that.
Stir in the garlic and saute until fragrant, about 1 minute more. Add the curry spices and saute briefly to flavor the oil (this is called tempering).
Pour in the vegetable broth and add the cauliflower florets. Stir to coat the cauliflower with the seasonings (it will be rather crowded in the Instant Pot).
Cover the Instant Pot and set to pressure-cook on high pressure for 5 minutes, with natural pressure release.
Use an immersion blender to partly puree the cauliflower and other vegetables to your preference. I like mine a little chunky but without large blobs of vegetables. You can add the coconut milk now or after you have processed the vegetables.
Add the cooked rice to the pot of soup and stir to incorporate. Set the heat to "slow-cook - high" and continue to simmer in the uncovered pot for about 5 minutes.
Taste and season with sea salt. (I usually add a little more salt once the rice has soaked up some of the flavor.)
Serve warm with the garnishes.
Leftovers can be refrigerated for up to 5 days or frozen for up to 1 month.
If the soup is thicker than desired after refrigerating and reheating, simply whisk in a bit more vegetable broth or filtered water and adjust seasonings as needed.