Add the potatoes to a large saucepan and cover with water. Place over medium-high heat and bring to a boil (keep an eye on it to prevent boiling over). Boil for 30 minutes, or until the potatoes are cooked through and a fork or metal skewer slides in easily. Drain well and pat dry with a clean tea towel.

Preheat the oven to 200°C (400°F). Lightly drizzle some olive oil over two large baking trays. Place the potatoes on the trays and, using a glass or another flat-bottomed object, gently press down to smash each one. Drizzle the tops with a little more olive oil, season with salt and pepper, and gently move the potatoes around to ensure they’re evenly coated in oil.

Roast in the preheated oven for 45 minutes to 1 hour, depending on the size of your potatoes and your oven. They're ready when they're golden brown and super crispy.

While the potatoes are roasting, make the dressing. In a large bowl, combine the Greek-style yoghurt, grated cucumber, chopped dill, lemon juice, and Dijon mustard. Mix well, then season to taste with salt and pepper. Set aside in the fridge until ready to use.

Once the potatoes are crisp and golden, roughly chop them into bite-sized pieces and add to the bowl with the dressing.