Melt the butter and oil in a large heavy-bottomed skillet over medium-high heat. Add the sage and fry until crisp, about 2 minutes. Remove the sage to a paper towel-lined plate. Add the squash to the skillet along with the nutmeg and a sprinkle of salt and pepper. Saute the squash, stirring occasionally, until browned and almost cooked through, 10 to 15 minutes. Lower the heat and continue to cook until the squash is soft and cooked through, about 5 minutes more. Remove to a serving dish, top with the shaved apple and sprinkle with the toasted pecans and sage leaves. Serve immediately.