Get your oven ready by preheating it to 200°C (or 180°C for fan-forced ovens). Line a baking tray with parchment paper for easy cleanup. Now, here's a handy trick: lay a wooden spoon on your countertop and position one potato at the rounded end. Carefully cut slits into the potato crosswise, spacing them about 3-5mm apart. The edge of the spoon will act as a guide, preventing your knife from going all the way through.

In a mixing bowl, add the potatoes along with the butter and a pinch of salt. Give them a gentle toss to ensure everything combines nicely. Arrange the potatoes on the prepared tray, cut side up. Roast in the oven for about 40 minutes or until they turn wonderfully crispy and tender. To serve, top them with a dollop of sour cream, crispy bacon, a sprinkle of fresh rosemary, and a touch of salt flakes.