Preheat the oven to 180ºC/fan 160ºC/Gas Mark 4.
Grease and line an approximately 20 x 30cm rectangular baking tin, 3 to 4cm deep, with nonstick baking paper.
Melt the butter and dark chocolate either in a bowl over a pan of simmering water or gently in the microwave.
With an electric hand whisk, beat together the eggs, sugar and vanilla extract until they are lovely and thick and creamy. Mix in the melted chocolate and butter. Finally stir in the flour, salt, white and milk chocolate.
Pour into the baking tin and cook for about 25 minutes until the top is cracking and the centre is just set. Leave to cool in the tin for about 20 minutes before cutting into squares.
Before serving, whip the double cream until it just starts to form soft peaks. Fold in the raspberry purée and liqueur (if using) and serve with the warm or cooled brownies.
For extra style to your plate, serve the brownies cut into circles using a cookie cutter, rather than standard squares.
The brownies and plate can be dusted with icing sugar or cocoa powder before adding the cream. Additional raspberry purée can be served in shot glasses on the plate to pour over the brownies.
See more cream recipes