In a large bowl with a tight fitting lid, place the wheat bran flakes (or plain wheat bran) and the bran buds or all-bran. Pour the boiling water over the bran and mix well. Stir every couple of minutes while the mixture cools to room temperature. The mixture will become very thick and sticky.
After the mixture cools, add the buttermilk, melted butter, applesauce, sugar, eggs and vanilla. Mix well. Add the flour, baking soda and salt. Mix well to combine all the ingredients together.
The batter can be covered well and kept in the refrigerator for up to 30 days. To bake, scoop the batter into greased or lined muffin tins. Bake at 400 degrees for about 20 minutes, until a toothpick inserted in the center of a muffin comes out clean or with a few moist crumbs.