Pulse dates in a food processor to break them up then add the sweet potato, honey, eggs, vanilla, milk and butter. Turn processor on high and let puree for about a minute until smooth. Pour into a large mixing bowl.
In a separate bowl, mix together the brans, flour, baking powder, baking soda, cinnamon and salt. Stir the dry ingredients into the wet ingredients then add the orange zest and walnuts.
Divide among a 12 cup muffin pan that has been generously sprayed with cooking spray. Smooth the tops with the back of a spoon.
Bake at 350 degrees for 25 minutes. Remove pan from oven and allow to cool completely.