In a large bowl, combine the flour, 1 cup sugar, baking soda and salt. Combine the buttermilk, egg and oil, stir into dry ingredients just until moistened. In a small bowl, combine the cinnamon and remaining sugar. Pam spray the bottom only of a
9 x 5 x 3 inch loaf pan. Pour half of the batter into pan; sprinkle with half of the cinnamon-sugar. Carefully spread with remaining batter and sprinkle with remaining cinnamon-sugar; swirl a knife through batter. Bake at 350 degrees for 45-50 minutes or until a toothpick inserted near the center comes out clean. Cool for 10 minutes before removing from pan to a wire rack to cool completely. For glaze, combine powdered sugar and enough milk to achieve drizzling consistency. Drizzle over bread.