Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 10 inch tube pan. Sift together the flour and baking powder. Set aside.
In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla and butternut extract. Beat in the flour mixture alternately with the milk, mixing just until incorporated. Pour batter into prepared pan.
Bake in the preheated oven for 60 to 80 minutes, or until a toothpick inserted into the center of the cake comes out clean. Let cool in pan for 10 minutes, then turn out onto a wire rack and cool completely.