Yeah, all you do is heat the oil in a frying pan, then fry the red onions for 10 mins until soft. add some sugar and balsamic vinegar, then cook for a further 5 mins until the juices are quite syrupy. Then you leave that to settle and cool down.
Then start unrolling the puff pastry onto a baking tray. Score a line a finger-width in from the edge all the way around, then cover the middle with the onion mix. Scatter the feta and olives over. Season and drizzle the extra virgin olive oil over the topping. (That is optional though)
Bake for 15 mins or until the pastry is risen and golden and the base is crisp.