Preheat the oven to 375°F and line a baking sheet with parchment paper.
In a large bowl, combine flour, bran, salt, baking soda, and baking powder. Whisk together.
In a separate bowl combine buttermilk and egg. Whisk to combine.
Make a well in the center of the dry ingredients and pour the buttermilk mixture into the well. Use a wooden spoon to gradually incorporate the wet and the dry ingredients together.
Knead the mixture in the bowl until smooth (if the mixture is too wet, you can add flour a teaspoon at a time until you get the desired consistency.)
Shape the dough into a round ball and place it on the lined baking sheet. Flatten the dough to about 2 inches in height.
Use a knife to score a cross shape on the top of the bread loaf. Sprinkle oats on top.
Bake 35-40 minutes. The bread is done when an inserted toothpick comes out clean. Or, the internal temperature of the bread is 180°F.
Let cool before cutting and serving.