Eggplant (US) or Aubergine (ENG) cake au gratin with Pesto (Pastís d´alberginia gratinat al pesto)

Pesto (italian dressing) is made of basil, pine nuts, some cheese called parmiggiano and salt and oil. Mix this pesto with some eggplant crushed like puree over a puff pastry. In a big saucepan, add some oil and then add at the bottom of it the eggplant or aubergine sliced and previously cooked in the oven (au gratin, with oil and salt), then add the puree of eggplant and the pesto and some more pine nuts toasted and then add the puff pastry. Put it in the oven for 25 minutes 200ºC (400ºF) or so and then turn it upside down.