Heat coconut oil in a large stockpot over medium heat. Add onions and cook until soft. Then add in garlic, ginger, jalapeño, lemongrass, curry powder, cumin, turmeric, salt, and pepper. Stir and cook for 5 min. (should be fragrant).
Add vegetable stock, coconut milk, and 1 cup of water. Bring to a boil and add the yams and carrot. Lower the heat and simmer with the lid on for 20 min., stirring occasionally. Once yams are soft, either use an immersion blender or spoon into a blender to get a smooth consistency. Return to the pot, off the heat.
Stir in the lime juice, soy sauce, and brown sugar. Put the lid on let rest for 10 min. Add more salt if needed. Garnish with cilantro and green onion.