Mix first 6 ingredients. Add eggs, buttermilk, oil, and mix thoroughly.
Cover batter and refrigerate overnight before using. (Spray muffin pans with
non-stick spray) Bake at 400 degrees for 20 minutes or at 350 degrees for 25
minutes. Batter will keep in the refrigerator for 6 weeks. Muffins may be
frozen after being baked.