Step by step

Pour a layer of sauce into a baking dish, then a layer of aubergine, and then another of sauce.

Tips
To prepare the best ‘parmigiana’, you should buy top quality, large aubergines, oval, shiny and light purple; they should not prove neither too hard nor too soft to the touch.
Trivia
The first recipe for baked aubergine with parmesan seems to have been written in ‘Il cuoco galante’ by Vincenzo Corrado, an author originally from Puglia but who was in service with various Neapolitan families.