In a large bowl combine the butter, egg. vanilla and sugar. Stir in the baking powder and salt until combined. Next stir in the milk and then the flour, mixing until combined. The batter will be barely lumpy.
Finally stir in the white chocolate and lastly the raspberries.
Fill the liners evenly with all the batter.
Bake the muffins for 20-25 minutes until the centers are set.
Remove the muffins from the tin and place on a wire rack to cool.
For the glaze whisk together the powdered sugar and the milk until it’s smooth.
Dip the tops of the muffins into the glaze while they’re still warm.