• Adjust the oven rack to the lower third position and preheat the oven to 350°F (177°C). Lowering the oven rack prevents the top of your bread from browning too much, too soon. Grease a metal 9×5-inch loaf pan with non-stick spray. Set aside.
• Whisk all-purpose flour, baking powder, baking soda, and salt in a large bowl until combined.
• Whisk eggs, and granulated sugar in a medium bowl until well combined about 35 seconds. Add melted butter, sour cream, and vanilla; mix well.
• Pour the wet ingredients into the dry ingredients and gently whisk until dry ingredients are moistened. The batter will be thick.
• Gently fold in the chopped white chocolate and raspberries.
• Pour batter into prepared loaf pan and even out with a spatula.
• Bake for 60-70 minutes, or until toothpick comes out clean. Baking times vary so keep an eye on it. The bread is done when a toothpick inserted in the center comes out mostly clean with zero raw batter. Remove the bread from the oven.
• Cool cake in the pan set on a wire rack for 15 minutes before removing from the pan. Carefully remove loaf from pan. Let cool completely on wire rack.

White chocolate icing

• When the cake is cool, make the white chocolate icing. Place white chocolate chunks or white chocolate bar broken into pieces into a microwave-safe bowl. Heat no more than 20 seconds at a time. Each time you heat the chocolate, take it out of the microwave and stir. Continue to heat and stir until the white chocolate is fully melted, it is easy to burn white chocolate. Stir until white chocolate is smooth. Add butter and mix with a whisk until combined. Add the powdered sugar, salt, vanilla, and milk. Whisk until smooth. Drizzle the white chocolate icing over the cooled loaf cake. Cut into slices and serve.