Preheat the oven to 350 degrees Fahrenheit. Line a 9x5 loaf pan with baking spray and set it aside.
In a medium sized bowl, stir together the dry ingredients; the flour, baking soda, cinnamon, baking powder, and salt until combined. Set it aside.
In a large bowl, cream together the butter, sugar, and brown sugar for about 2 minutes until light and fluffy.
Add the egg and stir it in.
Add in the buttermilk, and vanilla extract, and slowly stir it in until combined.
Add the dry ingredients to the wet ingredients, and stir them together until just combined, with no dry patches.
In a small bowl, stir together the sugar and the cinnamon.
Add half the batter to the pan and smooth out the top.
Sprinkle 2/3 of the cinnamon sugar mixture evenly over the top of the batter.
Spoon the remaining batter evenly over the top.
Add the remaining cinnamon sugar over the top of the batter. Gently swirl it with a butter knife.
Bake the bread for 40 to 50 minutes, until a toothpick inserted into the center comes out clean.
Let the bread cool for 10 to 15 minutes in the bread pan, then remove it from the pan and let it cool completely on a wire rack.