- Heat oil in the pan over medium heat. Add onion to the pan and sauté for 5 minutes or until golden brown. Add cinnamon, garam masala, turmeric, coriander, cumin, and garlic and cook for 2 minutes. Transfer onion-spice mixture into the slow cooker.
- Add lentils and stock into the slow cooker and stir well. Cover and cook on low for 4 hours. Add coconut milk and spinach. Stir well and cook for another 30 minutes. Season with pepper and salt. Serve and enjoy.