• Take a piece of baking parchment large enough to line a baking sheet and draw a rectangle roughly 20cm x 30cm on it. Turn it upside down so the pencil lines are on the bottom, facing the tin. 
• Place the dark chocolate in a microwave-safe bowl and melt it in a microwave in 20-second intervals, stirring with a spatula, until smooth. 
• Use the spatula to spread the chocolate evenly within the lines of the rectangle. 
• Melt the white chocolate the same way. Once smooth, add a blob of food colouring paste (I used red) and stir until the chocolate turns pink. (Or just leave it white.)
• Drizzle the melted white/pink chocolate in lines over the dark chocolate. Then use a cocktail stick to make swirly patterns. 
• Sprinkle with the mixed fruits and nuts — I bought a snacking mix containing cashew nuts, dried strawberries, cranberries and tiny chunks of white chocolate. Add a couple of pinches of sea salt flakes if you like. 
• Cover and leave to set —  about 2 to 4 hours.
• You could wrap the whole slab in cellophane as it is, or breake it into pieces, then wrap it in cellophane bags. It keeps for at least a week in an airtight container with parchment between the pieces.

Wrap the whole bar in cellophane or break into shards and bag up.