Preheat oven to 180C/350F/G4
Slice the aubergine into rounds approximately 0.5cm/1/4" wide and layer in a colander with salt for 20 mins, then rinse and pat dry.
Saute the onion and garlic in 1 tbsp of the olive oil for 5 minutes.
Add the green lentils, mushrooms, chickpeas, tomato puree, tinned tomatoes, oregano, thyme, bay leaf, stock and water - bring to the boil then lower heat and simmer for 10 minutes. Season with salt and pepper
Fry the aubergine slilces in the remaining tablespoon of oil for 5 minutes, flipping after 3 minutes.
Make the creamy topping by beating together the egg, parmesan cheese, yogur and nutmeg. Season to taste.
In an oven proof dish layer the aubergine slices with the vegetable mixture. Top with the cheese sauce and sprinkle with extra cheese then bake for 40 minutes till golden