Heat the olive oil in a large pot over medium heat. Add the diced onion and cook for 4 minutes until softened.
Stir in the minced garlic and cook for 1 minute more.
Add the cubed sweet potatoes, rinsed red lentils, vegetable broth, cumin, turmeric, and paprika. Bring the mixture to a boil.
Reduce heat to low, cover, and simmer for 20 minutes until the sweet potatoes and lentils are very soft.
Remove the pot from heat. Use an immersion blender to puree the soup until smooth, or transfer to a countertop blender in batches.
Return the pot to low heat. Stir in the coconut milk and season with salt and black pepper. Heat through for 3 minutes.
Ladle into bowls and top with fresh cilantro before serving.