Preheat the oven to 350℉. Spray the bottom only of a 9x5-inch loaf pan.
In a large bowl, whisk together the flour, 1 cup sugar, baking soda and salt. Stir in the raisins. Add the buttermilk, egg and oil, and stir to combine until moistened.
COMBINE THE CINNAMON/SUGAR:
In a small bowl, combine the ½ cup sugar with the cinnamon.
CREATE THE LOAF
Pour half of the batter into the prepared pan. Sprinkle with half of the cinnamon-sugar. Carefully, spoon in the remaining batter. Sprinkle with the remaining cinnamon-sugar. Cut throught the batter with a knife to swirl.
Bake 45 to 50 minutes, or until a toothpick inserted near the center comes out clean. Cool for 10 minutes, and then remove the bread to a wire rack to cool completely.
ADD THE GLAZE:
In a small bowl, whisk together the powdered sugar and milk. Drizzle the glaze over the top of the loaf.
Notes
Don’t overmix: Stir just until combined for a tender loaf
Swirl lightly: This keeps the cinnamon sugar layered instead of blended
Check doneness: Insert a toothpick in the center—should come out clean
Optional add-ins: Nuts or golden raisins work well