Preheat the oven to 425°. Line your muffin pan with your favorite cupcake wrappers.
In a liquid measuring cup, melt ½ cup of butter. Allow the butter to cool.
Combine the flour, sugar, baking powder, baking soda and salt in a large mixing bowl. Whisk to combine.
In a large measuring cup, combine the melted and cooled butter, sour cream, whole milk and vanilla. Whisk until well combined.
Add liquid ingredients and eggs to the dry ingredients. Mix until the batter just comes together. Be careful not to over mix.
Gently fold the frozen raspberries and chopped white chocolate into the batter.
Scoop the batter into the lined muffin pan. Fill each cup about ⅔ of the way. I like to use a large cookie scoop to do this.
Bake muffins at 425° for 5 minutes. Lower the oven temperature to 350° and bake for an additional 15-17 minutes. Muffins should have golden brown edges and the middles should bounce back a little when you poke them.
Remove muffins from the oven and allow to cool for 5-10 minutes in the pan. Move muffins to a cooling rack and allows to cool completely before drizzling with white chocolate.