Add the onion, cinnamon stick, bay leaves, cumin, salt and pepper and cook for 1 minute.
Add the garlic and cook for another one minute.
Add the walnuts and lentils and cook for 20 more minutes (add a splash of water during cooking, if needed).
For one full cup of cooked lentils, you'll need about half a cup dried lentils. Boil them while preparing the vegetables to save time.
For serving, I like to mix some sauce with the pasta, and then top with some extra.