Preheat the oven to 165°C.
Melt the butter in a microwave-safe dish. Set aside.
Melt 90g of chopped white chocolate in a heatproof bowl over a pot of boiling water (double boiler method). Set aside.
In a mixing bowl, whisk the sugar and eggs together. Add the vanilla extract, melted butter, and melted chocolate, mixing until well combined.
Stir in the flour and 90g of chopped white chocolate.
Gently fold in the raspberries (halved if large).
Pour the mixture into a 20 x 20 cm baking pan lined with parchment paper and bake for 30 minutes. Cover with aluminum foil if the brownie begins to brown too much.
Allow to cool for 20 minutes before demoulding. Garnish with powdered sugar and/or raspberries.