Preheat oven to 400 degrees. Line a 12-cup muffin pan with cupcake liners.
In a ramekin or small bowl, mix 1 tablespoon flour and 1½ tablespoons of sugar to sprinkle on top of muffins before baking.
In a medium to large bowl mix the flour, baking powder and chopped white chocolate and set aside.
Cream butter and ½ cup sugar until smooth (about 2-3 minutes). Add the egg and vanilla, then beat until incorporated. Add milk, then beat for 30 seconds. Scrape sides of bowl and mix another minute.
Add dry ingredients to wet in two batches. When dry ingredients are almost fully incorporated, hand stir in the raspberries. This will keep you from over mixing the batter which will cause your muffins to be dry.
Pour batter into prepared muffin cups. Dust the tops of all the muffins with the sugar/flour mixture from the ramekin. Place in preheated oven and bake for 18 minutes. Let cool and serve.