Preheat oven to 180°C. Pour oil into a large saucepan over a medium heat. Add cumin and mustard seeds and fry until the mustard seeds begin to pop. Add the sliced onion and turn the heat down to low. Slow cook the onions until soft and slightly brown, about 5 minutes. Add the garlic, ginger, turmeric and chilli powder and cook for a further 2 minutes.
Add the lentils, So Good™ unsweetened coconut milk, water and salt, then slowly bring to the boil, stirring regularly. Add the lemon and cook for about 15 minutes. Cover the pan with foil and place in oven for 15 minutes or until the lentils are cooked and starting to break down.
To finish the dhal, remove the lemon and carefully squeeze in the juice. Check the seasoning and pour into a serving bowl.
To make the Tarka
Heat the oil in a frypan and add the seeds and curry leaves. Fry until the seeds pop then pour over the top of the Dhal.