Grease and line a 20cm (8 inch) square cake tin. Break the White Chocolate into pieces and place in a saucepan. Add the butter and put over a very low heat, stirring occasionally, until melted. Remove from the heat, transfer the melted mixture to a heatproof bowl and leave to cool for 10 minutes.
Stir in the biscuits, dried fruit, nuts, mini marshmallows and Vanilla Extract. Mix well to make sure all the pieces are coated in chocolate and spoon into the prepared tin; press the top down to pack the mixture into the tin. Cool and then chill for at least 2 hours until set.
To serve, stand at room temperature for about 15 minutes, then remove from the tin and peel away the lining paper. Using a large sharp knife, cut into 16 squares. Your rocky road squares are now ready to serve and enjoy!