Heat oil in a medium saucepan over medium-high heat. Sauté onion for 3-4 minutes until tender. Add carrot, cook, stirring for 2 minutes. Add cumin and cook for 1 minute until fragrant

Add sweet potato, lentils and 2 cups (500ml) water. Bring to the boil and simmer, covered for 15-20 minutes until lentils and vegetables are tender

Remove from heat; cool slightly. Puree with a stick blender until smooth