Skillet Cornbread

Southern Living-mistakes women make in southern cooking: cornbread: melting butter in cast iron skillet then pouring butter in mix. This is not shown when you click: recipe. If you look at video, bacon grease is used in skillet in oven, not poured back in cornbread mix, then mix is poured in skillet on top of bacon grease.  So which is it?  butter or bacon grease?  pour it back in mix or not?  someone please get this together.  thank you. Nancy Aldridge