Heat the coconut oil in a large soup pot over medium heat. Add the onion, carrots, and sweet potato; cook, stirring, until the onion is softened and the edges of the sweet potato just start to color, about 5 minutes.

Stir in the ginger, garlic, curry powder, turmeric, cumin, and cayenne (if using); cook 1 minute, stirring constantly, until deeply fragrant. This blooming step is what gives the soup its golden color and depth — don’t rush it.

Stir in the rinsed red lentils, then pour in the vegetable broth, scraping up any browned bits from the bottom of the pot. Bring to a lively simmer.

Reduce the heat to medium-low and cook, partially covered, until the lentils have broken down and the sweet potato is completely tender, about 15 minutes. Stir every few minutes so the lentils don’t stick.

Remove the pot from the heat. Blend about half the soup with an immersion blender (or blend 3 cups in a countertop blender and return it to the pot), leaving plenty of texture behind. Stir in the coconut milk until the soup turns golden and silky.

Stir in the lime juice, salt, and black pepper. Taste and adjust — more lime for brightness, more salt to sharpen the spices. Ladle into bowls and finish with cilantro, extra lime wedges, and warm naan on the side.