Carefully slice thin slices into the potatoes, taking care not to cut through.
Place the potatoes on a sheet pan or in a baking dish then drizzle over olive oil (you can also brush the potatoes with melted butter) and season generously with salt and pepper.
Place the potatoes in the oven and allow to bake for 30-45 minutes, depending on size, until the potatoes are crisp and golden on the outside and tender on the inside.
While the potato bakes make the bacon butter. In a small bowl, mix the softened butter, crispy bacon, finely chopped sage, salt and pepper.
Serve the crispy potatoes with a generous dollop of bacon butter.