In a large bowl combine flour, baking powder, soda and salt. Stir well. Push up around sides of bowl making well in cetner.
In combine vinegar and milk with bran. Let stand 5 minutes.
Add remining ingredients to bran mixture in order given. Beat with spoon until mixd. Pour into well in flour mixture and stir to moisten. Batter will be lumpy. Fill greased* muffin cups 3/4 full. Bake at 375 for 20-25 minutes. Let stand 5 minutes. Remove from pan.
*there's not a lot of oil in these and they will stick if the cups are not greased/sprayed with non-stick spray.