Make these ahead, and freeze up to 1 month, if desired. Thaw muffins at room temperature 2 hours.
Combine first 5 ingredients together in a bowl; make a well in center of mixture. Combine buttermilk and next 4 ingredients; add to dry ingredients, stirring just until moistened. Do not overmix.
Spoon batter into greased muffin pans, filling two-thirds full.
Bake at 400° for 18 to 20 minutes or until lightly browned. Remove from pans immediately.