Preheat the oven to 200C/400F. Line a large baking sheet with parchment paper and set aside.
Wash and dry your baby potatoes. Using a sharp knife, cut slices crossways, ensuring there is an 1/8 inch remaining from the bottom. Rub olive oil around each of the potatoes and place them onto the lined sheet.
Sprinkle salt and pepper all over the potatoes before baking them for 45-50 minutes. Remove them from the oven and drizzle the melted butter over them. Place back in the oven and cook for a further 5 minutes.
Remove the potatoes from the oven and serve immediately.
TO STORE: Baked Hasselback potatoes should be stored in the refrigerator, covered. They will keep well for up to 1 week.TO FREEZE: Place leftover potatoes in a ziplock bag and store them in the freezer for up to 6 months.REHEATING: Either reheat in the microwave for 1-2 minutes, or in a preheated oven at 200C/400F for 6-7 minutes, until crispy.