Preheat the oven to 350°F (175°C) and line a muffin tin with cupcake liners.

In a mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

In another bowl, whisk together the flour, baking powder, and salt.

Gradually add the dry ingredients to the wet mixture, alternating with the milk, and mix until just combined.

Gently fold in the mashed raspberries and white chocolate chips.

Divide the batter evenly among the cupcake liners, filling each about 2/3 full.

Bake for 18-20 minutes or until a toothpick inserted into the center comes out clean.

Allow to cool completely on a wire rack before frosting.

In a mixing bowl, beat the softened butter until creamy.

Gradually add the powdered sugar and mix until combined.

Add the heavy cream, vanilla extract, and melted white chocolate, and beat until smooth and fluffy.

Frost the cooled cupcakes with the white chocolate frosting.