Preheat oven to 400 degrees F (200 degrees C). Grease two baking sheets.

Whisk together the egg, buttermilk, and molasses in a bowl until evenly blended; set aside. Stir together the whole wheat flour, all-purpose flour, bran, cream of tartar, and baking soda in a separate large bowl, and make a well in the center. Pour the buttermilk mixture into the well, and stir until a soft dough forms. Stir in the golden raisins, then turn the dough out onto a well floured work surface, and knead 8 to 10 times before dividing into two round balls. Place the balls on the baking sheets and use a sharp knife to cut a 1/2 inch deep X into the tops of the dough balls. Brush with melted butter.

Place the loaves into the preheated oven, and reduce the temperature to 325 degrees F (165 degrees C). Bake for 25 to 30 minutes until golden brown. Wrap the loaves in light cotton towels for 10 minutes after they are removed from the oven.