Preheat oven to 350F degrees. Coat a pie plate or 8x8 baking dish with nonstick cooking spray.
In a mixing bowl, whisk the flours, baking soda, baking powder, sugar and salt.
In a separate bowl, stir buttermilk, egg and melted butter together.
Make a well in the center of the bowl of flour mixture. Pour the buttermilk into the well. Use your hands to work the flour into the buttermilk until a loose dough forms.
Dump the dough onto a work surface and bring the dough together into a ball. Place the dough ball into the prepared baking dish and flatten it slightly into a disc shape.
Use a sharp knife to score the dough. Brush the top of the loaf with extra buttermilk.
Bake for 50 minutes, until the exterior is golden brown. Cool in the baking dish for 5-10 minutes, then transfer to a wire rack until the bread reaches room temperature.