Preheat the oven to 200'C / Fan 180'C / Gas Mark 6.

Set a large pan of unsalted water on the hob to boil. Meanwhile, peel the potatoes and cut the in halves (or quarters if they're particularly large - you want them around 2 x 2 inches in size).

When the water is boiling, tip in the potatoes and boil for 5-7 minutes, until the surface just feels a little soft when poked with a dinner knife.

Meanwhile, pour the oil into a large roasting tin and place in the hot oven to heat up - you want this in there for around 10-15 minutes so that it gets nice and hot.

Drain the potatoes in a colander. Give them a gentle shake to rough up the edges.

Carefully remove the roasting tin from the oven and pour the potatoes in - the oil should sizzle and spit. Use a slotted spoon to quickly turn them to coat them in oil, then as quickly as possible place back in the oven. Roast for 30 minutes.

While the potatoes are roasting, mix together the lemon juice, stock, oregano, crushed garlic and a good pinch of salt and pepper. Set to one side until the potatoes are ready (it doesn't matter if it goes cold).

When the potatoes have had 30 minutes, remove the tray from the oven and give them a shake to roll the potatoes round the tin. Pour over the lemon mixture, then shake again to ensure the potatoes are covered.

Place back in the oven for another 30 minutes, turning the potatoes half way through. When done, they should be golden and crunchy and the marinade should have soaked into the potatoes completely.

Pour into a serving dish, sprinkle over the fresh parsley and a pinch of sea salt flakes, and serve immediately.