Preheat the oven to 350℉. Line a standard 12 cup muffin pan with cupcake liners.
Add the cake flour, baking soda, baking powder and salt to a small bowl. Mix well and set aside.
Add the softened butter and the white sugar to a mixing bowl. Mix on medium speed until the mixture looks crumbly and then smooths back together, about 2-3 minutes.
Add the sour cream, milk, eggs, and vanilla. Mix on medium speed until fully combined and fluffy, about 1 minute.
Next, add the flour mixture and mix on medium just until combined, no more than 1 minute. Do not over-mix. A few small lumps are fine.
Fold in the frozen raspberries and white chocolate just until evenly distributed.
Using a large cookie scoop (the ¼ cup size), add one scoop of batter to each of the cupcake liners. If you don't have a cookie scoop, use a ¼ cup measuring cup. If needed, gently twist the muffin pan back and forth to level out the batter in the cups.
Bake for 19-20 minutes until the tops spring back lightly when touched and the edges are starting to brown. Remove the pan from the oven and allow the cupcakes to cool in the pan for 5 minutes. Remove the cupcakes from the pan and transfer them to a cooling rack to fully cool.