Preheat and prepare pan. Position a rack in the center of your oven and preheat the oven to 350°F (177°C). Spray a 8x4” loaf pan with cooking spray, or line with parchment paper and then spray with cooking spray.
Make the swirl. In a small mixing bowl, stir together the sugar and cinnamon. Set aside.
Soak the raisins. In a small bowl, cover raisins with hot, boiling water and let soak for 5 minutes. Drain and pat dry with a paper towel.
Combine dry ingredients. In a mixing bowl, whisk together all-purpose flour, sugars, baking powder, and salt. Set aside.
Combine wet ingredients. In a second mixing bowl, whisk together eggs, sour cream, melted butter and vanilla.
Combine wet and dry ingredients. Add the dry ingredients to the wet ingredients and mix together with a spatula or wooden spoon just until just combined. Fold in raisins. Do not overmix.
Assemble the bread. Spoon ½ of the batter into prepared loaf pan. Sprinkle on ½ of the cinnamon sugar mixture . Spoon the rest of the batter on top. Sprinkle on remaining cinnamon sugar mixture.
Bake. Bake in a preheated 350°F (177°C) oven for 60-65 minutes until a toothpick inserted into the middle of bread comes out clean or with a few moist crumbs clinging to it (no wet batter) and top springs back to the touch when lightly touched. Remove from the oven and cool completely in the pan on a wire cooling rack.
Make glaze. In a small mixing bowl, whisk together the powdered sugar, milk and vanilla. Adjust consistency if needed. Drizzle over bread before serving.