Grease and line an 8 inch spring form tin with baking paper.
Blitz one packet of milk chocolate Tim Tams in a blender to crumbs. Add the melted butter and mix well. Tip the crumbs into the baking tin and, using lightly damp hands, press it firmly over the base.
Stand Tim Tams on their short end around the side of the tin, alternating between milk and dark chocolate Tim Tams, nice side against the tin. Place in the fridge until needed.
Place the chocolates in two separate microwave safe bowls. Melt in the microwave on 30 second bursts, stirring well between each, until just melted. This should take no more than 2 minutes. Set aside.
Using a hand blender, beat together the cream cheese, sugar and sour cream. Make sure to scrape down the sides of the bowl regularly.
Split the cream cheese mixture evenly between two bowls. Pour the melted milk chocolate into one and the dark chocolate into the other. Gently fold through with a spatula.
In a separate bowl whip the cream until you have soft peaks. Gently fold a quarter of the mixture into the milk chocolate cream cheese. It's important to fold this until just incorporated so you don't beat out the air.
Add a spatula full of whipped cream to the dark cream cheese and beat it in quickly to lighten the mixture. Now add the rest of the cream and gently fold it through.
Tip the dark chocolate mixture into the tin and level out as much as you can. Now repeat with the milk chocolate mixture. Place in the fridge to set for at least 2 hours
Right before serving, top with whipped cream, the remaining Tim Tams (cut in half on the diagonal) and chopped chocolate.
I use a standard Australian 20ml tablespoon (4 teaspoons worldwide)
For best results you should always weigh ingredients like flour and sugar. Kitchen scales like these are relatively cheap but if you can’t weigh the ingredients, use the spoon and level method (don’t scoop).
TOOLS USED IN THIS RECIPE
A stand mixer or handheld beater
An 8 inch round spring form tin
I obsessed with my silicone spatula to make sure all the mixture gets into the pan