In a large pot or Dutch oven, heat coconut oil over medium heat.
Add the chopped onion and sauté for 5-7 minutes, or until softened and translucent.
Stir in the garlic and ginger, cooking for an additional minute until fragrant.
Sprinkle in the curry powder, turmeric, and cumin, stirring well to coat the onion mixture in the spices.
Pour in the vegetable broth and bring it to a boil. Add the cubed sweet potatoes and red lentils, then reduce the heat to a simmer.
Cook for 20-25 minutes, or until the sweet potatoes are tender and the lentils are cooked through.
Stir in the coconut milk and spinach, allowing the soup to heat through for an additional 5 minutes.
Season with salt and pepper to taste, then remove from heat.
Serve the soup hot, garnished with fresh cilantro.