Before cooking, follow on-pack instructions to rinse and pick over uncooked lentils.
In a large saucepan on medium heat, heat oil and sauté onion for 4-5 minutes without browning. Add garlic and ginger and cook for 1 minute.
Add the curry powder, cumin and pepper and stir to coat onions. Add the uncooked Whole Green Lentils, milk and stock. Stir and cover. Simmer for 15 minutes, adding more liquid if the mixture looks dry.
After 15 minutes, add the uncooked Red Split Lentils and cook for a further 10 minutes, stirring and adding more liquid if necessary.
Fold in the spinach, lemon juice and chopped coriander. Heat through and serve with rice and naan bread.