Preheat oven to 180°C (160°C fan/ Gas Mark 4). Grease and line a square 20cm baking tin.

Melt the dark chocolate and butter together in a heatproof bowl set over a pan of simmering water, or in the microwave in 30-second intervals, stirring until smooth.

Remove from the heat and stir in the caster sugar until well combined.

Beat in the eggs one at a time, mixing well after each addition.

Gently fold in the flour and cocoa powder until just combined. Be careful not to overmix.

Stir through the white chocolate chips and melted Nutella.

Pour the brownie mixture into the prepared baking tin and spread evenly.

Bake for 20-25 minutes, or until a skewer inserted into the centre comes out with moist crumbs attached.

Allow to cool completely in the tin before decorating.

To make the ganache: Heat the double cream in a saucepan until just simmering. Remove from the heat and pour over the dark chocolate. Allow to stand for a minute, then stir until smooth and glossy.

Pour the ganache over the cooled brownie and spread evenly.

Decorate with fresh raspberries and sprinkles.

Cut into squares and enjoy!