Preheat the oven to 210°C, drizzle a little olive oil in a baking tray big enough for the potatoes and place in the oven. Start by par-boiling the potatoes for 10 minutes in heavily salted water. Drain and return to the saucepan, add the cornflour and a sprinkling of salt and pepper. Place the lid on and give the potatoes a good shake to fluff them up a little.
Tip the potatoes into the preheated tray and place in the oven. Cook for 30 minutes.
While the potatoes cook make your dressing by whisking all of the ingredients together.
When the potatoes have finished cooking place the in a large bowl with the spinach leaves. Cover with a tea towel and leave to wilt for a few minutes then tip onto a large plate. Top with the cucumber, tomato, pomegranate, chopped parsley and the dressing.