Ingredients

Step by step

1. First, tip the lentils into a bowl and cover with 600ml water; leave to soak for 1 hour.
2. Preheat the oven to 200°C, fan 180°C, gas 6. Lay the aubergine slices on a grill rack in a baking tin and brush them lightly with the oil. Sprinkle lightly with sea salt and roast in the oven until soft and lightly browned, about 10 minutes. Alternatively, brush the slices lightly with oil and cook in a preheated griddle pan for 2-3 minutes on each side until tender and griddle marks appear. Meanwhile, put the thinly sliced sweet potatoes in a bowl of cold water until ready for use.
3. For the lentil and tomato sauce, heat the oil in a saucepan. Add the onion, garlic, cinnamon and oregano and fry gently until fragrant, stirring occasionally. Add the tomato purée and keep stirring until well mixed. Now add the lentils, the water they have been soaking in and the tomatoes. Bring to the boil, reduce the heat to medium-low, cover and simmer for 30-40 minutes, until the lentils are soft and the sauce is 'dry'; add the salt to season.
   Tip

   Short of time? Use 2 x 410g tins of green lentils instead of dried. Make the tomato sauce as per step 3, simmer for 20 minutes, add the lentils, drained, 300ml water and simmer for a further 10 minutes.
4. Make the béchamel sauce by heating the oil in a small saucepan over a medium-low heat. Add the flour and stir until thick and slightly browned. Whisking constantly, add half the milk, whisk again, then add the remaining milk, whisking until smooth. Add the nutmeg and some seasoning. Cook, whisking constantly, until the sauce comes to the boil and thickens.
5. Reduce the oven heat to 180°C, fan 160°C, gas 4. Arrange a third of the aubergine slices in the base of a fairly large baking dish – about 2.5 litre capacity. Top with half of the sweet potato slices and half of the lentil and tomato sauce. Repeat. Finish with the remaining aubergine slices and then pour the béchamel sauce over.
6. Bake the moussaka for 45 minutes to 1 hour. Test to see if the sweet potatoes are tender by inserting a sharp knife down through the centre. Remove from the oven and leave to cool for 15 minutes. Drizzle some olive oil over before serving.