Preheat oven to 400. Take your potatoes and cut small slits NOT ALL THE WAY THROUGH the potatoes. Heat up the butter and olive oil, remove from the heat and pour over the potatoes. Arrange on a baking dish cut side down first. Salt slightly, bake for 15 minutes. Turn to cut side up, gently, salt slightly, bake remaining 30 minutes until done and slightly crispy. Serve.