Preheat the oven to 400 degrees. Grease muffin tins or papers and set aside.
In a large bowl, pour the boiling water over 2 cups of All Bran. Let sit until the water is absorbed then mix in the melted butter.
In another bowl, mix the remaining All Bran with the sugar, eggs, and buttermilk.
In a third bowl, combine the flour, baking soda, and salt.
Stir all of the ingredients together.
Fill the muffin tins 2/3 full of batter and bake for about 20 minutes.
Notes:
Make Ahead: You can keep this batter for up to 6 weeks - just cover it tightly and store it in the refrigerator.The baked muffins freeze well too - just seal tightly before freezing.