Set oven to 400 F and start boiling 2 cups of water to blanche the potatoes
Peel, thinly slice potatoes and blanche them for 5 minutes. Drain and set aside.2. Add a little water and oil to a small baking tray and swirl around to coat the base so that the onions do not stick to the pan.
Slice onion as thin as you can and place them in the tray.
Add layer of blanched potatoes.
Sprinkle with half the oregano.
Salt and pepper both sides of fish filet, cut to serving size and lay over potatoes.
Sprinkle fish with other half of the oregano.
Slice tomato as thin as you can, layer over the fish and add salt.
Add a layer of sliced lemons
Sprinkle pitted and halved olives all over.
Bake for 15-20 minutes or until fish flakes off.
To serve, use a spatula to lift filets with tomato, lemon and olive toppings off the tray and on to a plate. Sprinkle coarsely chopped parsley then serve onions and potatoes on the side.