Combine condensed milk, both blocks of chocolate, vanilla paste and butter in the bowl of your slow cooker, keep the lid off, on high, stirring every 15-20mins.

Crumble packet of Tim Tams into smallish chunks and set aside.

Once mixture starts to come together off the sides of the bowl and a crust forms between stirs, add Tim Tam chunks and stir through.

Pour into a baking paper lined slice tin and refrigerate for 3-4 hours or until set :)