Preheat the oven to 450°F.  Line a baking sheet with parchment paper, reserve.

Add the flours, bran, salt, baking soda and baking powder to a large bowl and whisk to combine.

Cut the butter into bits and rub it into the flour mixture with your fingertips until it resembles bread crumbs.

In a separate bowl or pitcher, whisk together the egg, buttermilk and molasses.

Make a well in the center of the flour mixture and pour in the buttermilk mixture. 

Stir the mixture together in a circular direction, beginning in the center, gradually working to the outside edge, incorporating the flour.  The dough will be soft and slightly sticky.

Tip the dough out onto a lightly floured surface and using your hands, gently shape the dough into a round, pressing it to about 2-inches thick and place on the parchment paper lined baking sheet.  

Using a sharp knife, cut a cross on the top of the dough.  Make a small incision in each section of the cross.

With a silicon pastry brush, glaze the dough with additional buttermilk and sprinkle with a tablespoon of oats.

Transfer to the oven and and bake for 15 minutes, then reduce the oven temperature to 400°F and bake an additional 25 to 30 minutes.

Remove the baking sheet from the oven and transfer the bread to a wire cooling rack.

To check for doneness, tip the bread on its side and tap the bottom. 

When done, the bread will sound hollow when tapped on the bottom and an instant-read thermometer will read 200°F.