Preheat the oven to 325°F (160°C).
Coat a 9" x 5" -inch loaf pan with non-stick spray and then line the bottom with parchment paper. If you have a non-stick loaf pan, simply coat it with non-stick spray.
In a large bowl, measure and mix together the dry ingredients. Break up the brown sugar with your hands and sift in the baking soda and baking powder just to make sure there are no lumps. Stir to evenly combine.
In a separate bowl, blend the egg. Then add a bit of the buttermilk and blend to evenly combine. Add the remaining buttermilk and blend again. *Note: Either low-fat or full-fat buttermilk will work for this recipe.
Form a well in the dry ingredients and pour the wet ingredients over top. Stir gently but quickly - just enough to moisten the dry ingredients. Don’t overmix as you do not want to develop too much gluten.
Pour or spoon the mix into the prepared loaf pan and place into the oven. Bake for approximately 50 to 60 minutes or until a wooden skewer inserted into the center comes out clean. The top should also be a nice, even golden color.
Once done, transfer to a cooling rack. Let it sit for about 5 minutes before removing from the loaf pan. Let cool before serving.