Preheat the oven to 350 degrees. In a small bowl, combine 1/2 cup sugar and 1 Tablespoon cinnamon. Set aside.
In a separate bowl, combine flour, baking soda, salt, and remaining sugar.
In a third bowl, combine buttermilk, egg, and oil.
Stir the buttermilk mixture into the flour mixture just until moistened.
Pour half of the batter into a greased 9x5x3-inch pan. Sprinkle with half of the cinnamon-sugar. Spread the remaining batter on top and sprinkle with remaining cinnamon-sugar.
Swirl knife through batter.
Bake 45-50 minutes, or until a toothpick comes out clean. Cool 10 minutes before removing from pan and cooling on wire rack.
Combine glaze ingredients and drizzle over bread when it has completely cooled off. Slice and enjoy.