Step 1: Preheat oven to 350°F (175°C) and prepare a 9-inch loaf pan with nonstick baking spray or butter.
Step 2: Sift together the all-purpose flour, whole wheat flour, baking soda, baking powder, and kosher salt into a large mixing bowl. Set aside.
Step 3: In a standing mixer fitted with the paddle attachment, cream together the softened unsalted butter and granulated sugar until light and fluffy.
Step 4: Add the eggs one at a time, mixing well after each addition until fully incorporated. Stir in the pure vanilla extract.
Step 5: Alternate adding the dry ingredients mixture and buttermilk to the wet ingredients in the mixer, beginning and ending with the dry ingredients. Mix until just combined, being careful not to overmix.
Step 6: Gently fold 1/2 cup of dried cranberries and 1/2 cup of white chocolate chips into your batter until evenly distributed.
Step 7: Pour the batter into the prepared loaf pan and spread evenly. Bake for 60-70 minutes, or until a wooden skewer inserted into the center comes out clean.
Step 8: Once baked, allow the loaf to cool completely in the pan on a wire rack before attempting to remove it. After removing from the pan, transfer the cranberry bliss loaf to a wire rack, placing a cookie sheet underneath it to catch any drips.
Step 9: In a medium mixing bowl, whisk together the powdered sugar, pure vanilla extract, and 2-4 tablespoons of milk until smooth and well combined. Adjust milk consistency as needed.
Step 10: Carefully pour the vanilla icing over the cooled cranberry bliss bread, allowing it to drip down the sides. Let the icing dry and set for at least 30 minutes.
Step 11: While the icing sets, melt the remaining 1/2 cup white chocolate chips using a double boiler or microwave. Finely chop the remaining 1/2 cup of dried cranberries. For chopping, a quality chef's knife will make the task easier.
Step 12: Drizzle the melted white chocolate over the iced loaf and then sprinkle with the chopped cranberries.
Step 13: Allow all toppings to set completely before slicing and serving.