I love that this soup is naturally thickened with the red lentils. Cooked red lentils are often more tender than brown, green or black lentils which allows them to blend nicely. I like the brightness that the uncooked apple gives the soup. If you’re using a more tart apple, you can cook them with the onions to help bring out their sweetness.
Add wilted or leftover greens such as swiss chard or kale to the soup after blending. You can also top this soup with savory garam masala granola.