A delicious pie for picnics, potlucks, lunch, or as a side dish with a simple main course such as baked chicken pieces or fish. If you have a mandoline, use that for slicing the onions, but a sharp knife and a cutting board will be just fine: pour a glass of wine and sit outside so your eyes don't burn! Note that you can choose which cheese to use: for the photo's I used Camembert, which goes on the bottom, and which will melt deliciously as you cut the pie. If the pie is to be eaten cooled or cold, use feta cheese, and put it on top of the pie as its reaction to oven heat is different from soft cheeses. I made this with feta for a picnic, but if it's to be eaten fairly soon after baking, I would use Brie or Camembert. Yummy!