Add the thinly sliced potato to the base of a baking tray.
Put lentils in a large saucepan with tomato, stock, oregano, salt, smoked paprika and onion. Simmer the lentils gently for 20 minutes or until the lentils are soft and most of the liquid has been taken up.
Pour half the lentil mixture over the potato.
Layer the eggplant over the lentils and reserve 3 slices.
Pour the remainder of the lentils over the eggplant.
Beat the egg and cream mixture and pour over the lentils carefully.
Add the reserved eggplant to decorate the Moussaka.
Spray the eggplant with olive oil to stop it drying out during cooking.
Sprinkle the dish with smoky paprika.
Cook the Moussaka covered for 15 minutes and remove the foil for the final 5-10 minutes.
Before serving check with a knife that the potato is cooked through.