1. Preheat oven to 350 degrees. Grease a 9 x 5 loaf pan with non stick cooking spray or butter.
2. In a large bowl combine flour, 1/2 cup brown sugar, baking soda and salt, set aside,
3. In a medium bowl combine buttermilk, vanilla, egg and oil.
4. Add the wet ingredients to the dry and mix until just combined.
5. In a small bowl combine the remaining 1/2 cup brown sugar and cinnamon.
6. Add half of the batter to the prepared loaf pan.
7. Sprinkle half of the cinnamon sugar mixture on top.
8. Pour the remaining batter in followed by the remaining cinnamon sugar mixture on top. Using a butter knife swirl the batter to marble the bread. (I do a couple figure 8's).
9. Bake for 40 minutes or until golden brown on top and a toothpick comes out clean.
10. Allow it to cool for 30 minutes in the pan and take it out to cool completely on a wire rack.
11. When it is cool drizzle with the glaze and serve.

Glaze

1. In a medium bowl combine the powdered sugar and milk. Whisk until it is smooth and clump free. Set aside until you are ready to drizzle ontop of the bread.