Melt the Caramilk chocolate in a heatproof bowl over simmering water (double boiler method) and allow it to cool slightly.
In a mixing bowl, beat the cream cheese, vanilla extract, and powdered sugar until smooth.
Gradually mix in the cooled melted Caramilk chocolate until combined.
In a separate bowl, whip the cream until soft peaks form. Gently fold the whipped cream into the cream cheese mixture until fully incorporated.
Line a rectangular dish or surface with baking paper. Lay the biscuits flat in a single row, slightly overlapping, and brush them lightly with milk to soften.
Spread the cheesecake mixture evenly over the biscuits, leaving a small margin around the edges.
Using the baking paper to guide, gently roll the biscuits and cheesecake mixture into a log shape. Wrap the log tightly in baking paper or cling film and refrigerate for at least 4 hours or overnight to set.
Before serving, melt the white chocolate (if using) and drizzle it over the log for garnish. Slice and enjoy!