Slice the eggplants (approx 0.5 inch thick) and arrange the slices in one layer on a baking tray lined with parchment paper. No oil needed. Bake for 25 min.
Boil the lentils following the instructions on the package.
Boil the potatoes with the skin on.
"No-ground meat" filling
Chop the onion, celery, carrots, pepper, and 2 garlic cloves, and cook them for 7-10 min in a bit of water.
Add the walnuts and mushrooms to the food processor and process until a rough paste forms.
Add the mushrooms/walnut paste and the spices (garlic powder, onion powder, smoked paprika, soy sauce, oregano, basil, black pepper) to the veggie pan.
Drain the cooked lentils and add them to the sauce and mix well.
Add the tomato paste and tomato sauce to the pan. Add more salt and pepper if needed.
Bechamel sauce
Soak the cashews in hot water for approx 10 min.
Add the soaked cashews, 2 garlic cloves, nutritional yeast, one cooked potato, nutmeg, 1/2 tsp salt and the juice from one lemon to the food processor. Mix until a creamy and smooth paste forms. Add a bit of water if the mixture is too thick.
Assembly
Spread a thin layer of the no-meat sauce on the bottom of a baking dish.
Peal the potatoes, slice them and arrange the slices in a layer to cover the entire bottom of the tray.
Add the remaining no-meat mix and spread evenly.
Arrange the eggplant slices in a layer over the no-meat.
Pour the bechamel sauce on top and spread evenly.
Bake uncovered at 375 °F for 40-45 min or until the top becomes golden.
Allow the moussaka to cool for at least 30 min before slicing it.