• Soak the lentils for 15 minutes in warm water.
• Preheat the oven to 400º F (200ºC).
• Prepare the layers. Lay the eggplant and sweet potato slices on an oiled pan.
• Sprinkle lightly with sea salt and roast in the oven for 10 minutes.
• Make the lentil stew by heating the oil in a saucepan. Add the chopped onion, leek, celery, fennel, and garlic. Sauté for 5 minutes and add the lentils and 30 fl oz of water. Add the tomato puree, nutritional yeast, and spices.
• Stir until the lentils are soft, but don’t let them lose shape. It should take about 15 minutes. The stew should be on the drier side but still creamy.
• Line up your eggplant and sweet potatoes and along with your lentils.
• Oil a pan where you are going to assemble the casserole.

Make the bechamel

• Start making the vegan bechamel by melting the vegan butter on a saucepan and adding the flour.
• When it starts to brown, cook it for 1 minute more and add the vegetable milk.
• Stir with a whisk until it starts to get creamy. Add the nutmeg, salt, and pepper. This sauce gets sticky very quickly, so; you should make it just when everything is ready to assemble. It all should take no more than 20 minutes.

Assemble

• Reduce the oven temperature to 350ºF (175ºC).
• Start assembling the dish by arranging the eggplant and sweet potato slices in the bottom of a medium baking pan.
• Continue by laying a layer of lentil stew, followed by a layer of bechamel sauce.
• Add another layer of sweet potatoes, then eggplants, lentils, and finish with bechamel sauce. Optionally top with grated vegan parmesan or regular one for a vegetarian version.
• Bake for 35-40 minutes. Test if the sweet potatoes are tender by inserting a sharp knife down through the center. Remove from the oven and leave to cool for 30 minutes before serving.