Preheat the oven to 200°C/gas 6. Place the potatoes in a roasting pan with the onions and sprinkle with the cumin, salt, pepper and add the cinnamon stick. Drizzle with the olive oil and mix really well with your hands then spread the tomatoes over the potatoes. Pour the water into the base of the pan and cover with kitchen foil and place in the oven. Bake for 45 minutes, then reduce the temperature to 180°C/gas 4. Remove the kitchen foil and bake for another 30 minutes or until the potatoes are tender. Once cooked allow the potatoes to cool slightly then place in a large mixing bowl. Add the vinegar and gently stir in the spinach until it has lightly wilted. Place in a serving dish and crumble over the feta cheese. The mixture should only be warm now so the cheese will not melt. Scatter the oregano over the dish and add a final drizzle of olive oil and some black pepper.
Try Warm Cyprus Potato and Tomato Salad with Feta and Oregano for a classic taste of the Mediterranean!