Wash the potatoes and cook in boiling water for about 20 minutes. Wash the sage, shake dry, pluck the leaves from the stems. Mix the olive oil, salt and pepper in a bowl. Drain the potatoes, rinse in cold water and cut in half horizontally. Thoroughly turn the potato halves in the marinade and cover the inside with a leaf of sage, press it down. Place the potato halves on a baking sheet and let them cook for about 25 minutes at 200 ° in the preheated oven (but you can also place them on a grill tray upside down on the grill, about 5-10 minutes).