1. Preheat the oven to 350 degrees F (180 degrees C). Grease the cups in two mini muffin pans.
2. In a large bowl, stir together the bran, flour, brown sugar, baking powder and cinnamon. In another bowl, whisk together the milk, oil and eggs. Add the milk mixture to the bran mixture, stirring until just combined. Fold in the chopped apple.
3. Spoon batter into the prepared muffin pans, filling each cup to the top. Bake for 12 to 14 minutes or until a toothpick poked into the middle of a muffin comes out clean.
4. Makes 20 to 22 miniature muffins.
Note
If you prefer, you can bake this batter as full-size muffins instead of miniature ones. Increase baking temperature to 375° F (190° C) and time to 20 minutes. You'll only get 6 to 8 muffins, though.