1 onion, peeled and halved lengthways
1 leek, topped, tailed and halved widthways
60ml (4 tbsp) sunflower oil
450g (1 lb) old potatoes, peeled
6 large eggs
salt and freshly ground black pepper
115g (4oz) Brie, cut into chunks
30ml (2 tbsp) freshly chopped
parsley