Preheat oven to 350°F and line a muffin tin with 12 cupcake liners.
In a mixing bowl, whisk together flour, sugar, baking powder, and salt.
In a separate bowl, whisk the melted butter, eggs, milk, vanilla, and melted white chocolate until smooth.
Add the wet ingredients to the dry and stir just until combined.
Gently fold in the raspberries.
Divide the batter evenly among the liners.
Bake for 18–22 minutes, or until a toothpick comes out clean.
Cool completely before frosting.
Beat the softened butter until creamy.
Add powdered sugar and mix until fluffy.
Beat in the melted white chocolate and vanilla.
Add milk 1 tbsp at a time until you reach a smooth, spreadable consistency.
Pipe or spread the frosting onto cooled cupcakes.
Top with a raspberry or a sprinkle of white chocolate shavings if you like.