In a Dutch oven or stockpot, heat the oil over medium heat.
Add in celery, onion, and leek. Sauté for 10 minutes.
Add in garlic, and sauté for 1-2 minutes, until fragrant.
Add the cooking broth and salt. Increase heat to high, and bring to a boil. Then reduce heat to low, and simmer, covered, for 20 minutes.
Turn off heat, add in coconut milk, and mix thoroughly.
Gently pour soup into a blender to purée (don’t fill more than halfway at a time), or use an immersion blender. Only blend until creamy. *If using a blender, be careful since soup will be hot! I recommend holding the blender lid down with a towel!*
Pour puréed soup back into the pot. Reheat if necessary.
Add garnish and serve immediately.