Preheat the oven to 180°C/Fan 160°C /Gas 4. Place the potatoes in a large saucepan of salted water and bring to the boil, then simmer for 20–25 minutes on a medium–low heat, or until tender. Drain in a colander and leave to steam-dry for 5 minutes.
Transfer the potatoes to a baking tray and toss with the oil, garlic cloves, herbs and salt. Use a potato masher, spatula or the bottom of a glass to smash each potato. You want to keep each potato in one piece but flatten it slightly.
Roast for 35–40 minutes or until golden and super crisp.
To make the smoky chilli butter, simply melt the butter with the paprika and chilli
flakes in a small saucepan over a medium–low heat. Transfer the roasted potatoes to a serving platter and top each one with a dollop of yoghurt. Squeeze the creamy garlic cloves out of their skins, then scatter over the dill and parsley. Drizzle everything with the smoky chilli butter and serve.