Preheat your oven to 200°C (390°F). Peel and cut the Maris Piper potatoes into halves or quarters.

In a large pot, combine chopped potatoes, rosemary, and a pinch of salt. Cover with water and bring to a boil. Simmer for 12 minutes until slightly tender.

Add olive oil to a baking dish and place in the preheated oven for 5 minutes until shimmering.

Drain the potatoes and discard the rosemary stems. Gently shake the potatoes to roughen their surfaces for crunchiness.

Transfer the roughened potatoes to the hot baking dish, drizzle with more olive oil, and sprinkle with salt. Roast for 45 minutes, turning halfway through.

After 45 minutes, turn the potatoes with a spatula and roast for another 45 minutes until golden brown and crispy.