Peel the potatoes, then slice any large potatoes into halves or quarters. Add the potatoes to a large saucepan of cold water, bring to a boil and boil for 7-8 minutes or until soft on the outside. Then drain and add them back to the saucepan. Shake the saucepan to fluff up the outsides, then leave to cool for 10-15 minutes.
Add a generous glug of olive oil to a roasting tray and place it on an oven shelf. Preheat the oven to 200°C fan / 425°F.
When the oven is ready, remove the tray and carefully drop the par-boiled potatoes onto the hot oil in the tray. Sprinkle with a generous pinch of salt, then mix. Roast for 45-55 minutes or until golden and crispy, turning halfway.
When the potatoes are nearly ready, add a splash of olive oil to a large pan on a medium heat. Add the garlic and cook for 1-2 minutes or until it begins to turn golden. Stir in the harissa paste and maple syrup, then cook for 2-3 minutes or until the sauce begins to thicken.
Add the roast potatoes to the pan and stir them into the harissa glaze, until all the potatoes are covered in the glaze, then remove the pan from the heat.
To serve, spoon the yoghurt over a large serving plate. Top with the harissa glazed roast potatoes, followed by the coriander leaves and a big pinch of salt. Drizzle over any sauce left in the pan, then squeeze over juice from the lemon wedges.