Heat the butter until the foam subsides. Add diced chopped onions, sprinkle with salt, stir to coat with butter. Allow to soften for about 5 minutes.
Add the chopped carrots, ginger, garlic and the spices. Stir and cook until softened, about 10 minutes.
Add the stock. Stock should cover the carrots mixture. If needed, add more stock or water to ensure they are covered by 1 inch. Bring the pot to a boil over high heat. Reduce the heat to medium and continue cooking until the carrots are tender and cooked through, about 10 to 15 minutes.
Puree the soup using either an immersion blender, or transfer to a blender. If transferring to a blender allow to cool slightly and secure the lid. Cover the lid with a towel for extra layer of protection in case any liquids escape.
Add enough coconut milk to bring the soup to the consistency you want. Add in the lime juice to brighten the flavors. Taste soup and adjust the seasoning with more salt and pepper.
To achieve a nice presentation, take any remaining coconut milk and drizzle over the top. A pinch of cayenne or freshly grated nutmeg on top will add a nice note at the end. Top with toasted pepitas