You can make fresh muffins daily or as often as you wish with this batter, which will keep in the refrigerator for about 6 weeks. –The Pentagoet Inn, Castine, Maine
Pour boiling water over All-Bran and set aside. Mix sugar and melted butter, beat in eggs, and stir in sour milk. Add All-Bran mixture. Combine flour, raisin bran, soda, salt, and dates. Stir into wet mixture. Store in refrigerator at least overnight. Bake in greased muffin tins at 400 degrees F for 20-25 minutes.