Heat 2 tbsp coconut oil in a large pan over medium-high. Add the diced onion and a pinch of salt and cook for a few minutes until soft and translucent
Add the garlic, ginger and turmeric and cook for another 30 seconds
Add the apple and lentils and stir to coat. Stir in coconut milk and 600ml water and bring to a boil
Reduce heat and simmer, stirring occasionally, until lentils are completely soft and dal is thick, 35-40 minutes
While the dal is cooking, heat another tablespoon of coconut oil in a frying pan until hot. Add the cumin, coriander seeds and garam masala and cook, stirring constantly, for around 30 seconds to toast. Add the sliced onions to the pan and cook on high heat. Avoid stirring too often, to get plenty of colour on the underside of the onions. Cook for around 3 minutes on high, then remove from the pan and set aside
Divide dal among bowls and top with the fried onions