Crush white chocolate Tim Tams until they resemble fine crumbs.
Mix Tim Tam crumbs with the cream cheese and Kahlua liqueur.
Place into the fridge/freezer for at least 20 minutes to harden.
Roll into 1 inch sized balls and place on a tray lined with baking paper and place back into the fridge for a further 20 minutes.
Place white chocolate and milk chocolate into a microwaveable bowl and microwave on 50% power for 2-3 minutes, stirring every 30 seconds, until chocolate is completely melted.
Place the balls into the bowl of melted chocolate (in batches) and use two teaspoons to roll the balls around until they are completely coated.
Remove balls with the teaspoons and allow any excess chocolate to drip off.
Place back onto the baking paper lined tray.
Place into the fridge to set for 1 hour.
Drizzle with melted white chocolate if desired.