Preheat oven to 400°F. Grease 2, 12-cup muffin tins, or line with paper or silicone liners.
Bring water to a boil, then remove from heat and stir in 2 cups of “All Bran” cereal; set aside.
Slightly melt butter (avoid over-heating it) and add to a large mixing bowl along with applesauce, sugar, eggs, buttermilk, baking soda, flours, and salt; stir to combine.
Add in the cereal mixture and mix well. Fold in the remaining dry cereal.
Fill muffin cups and bake for 15 minutes. Allow to cool before serving.