Preheat the oven to 375°F. Grease a 9" x 5" loaf pan., In a large mixing bowl, whisk together the flours, sugar, baking powder, baking soda, and salt., In a separate bowl, whisk together the starter, vegetable oil, orange juice, orange zest, and egg. Pour the wet mixture into the dry, stirring until evenly moistened. Stir in the figs and nuts., Transfer the dough to the prepared pan and sprinkle the top with sparkling sugar., Bake the bread for 55 to 60 minutes, until a paring knife inserted in the center comes out clean., Remove the bread from the oven and cool it on a rack in the pan for 15 minutes before turning it out of the pan and returning it to the rack. Cool completely before slicing., Store the bread, tightly wrapped in plastic, at room temperature for several days; freeze for longer storage.