Preheat the oven to 175C/350F.
Start making the filling: add the coconut oil to a saucepan and gently fry the onions, ginger, garlic, and spices until soft and tender.
Add in the rest of the filling ingredients cooked lentils, white and red onion, 1 tbsp cumin, cinnamon, maple syrup, tomatoes, and vegetable stock, bring to the boil, then leave to simmer it.
Meanwhile for the mash - add the sweet potatoes to a pan of boiling water, bring to the boil until softened
Drain the water from the pan of potatoes, then add the rest of the mash ingredients cumin and coconut milk and mash until smooth.
Add the filling to a large baking dish or 4 small dishes, then add the mash on top and a sprinkle of nutritional yeast.
Bake in the oven for 20 minutes, then serve with fresh coriander