Tim Tams are a bit of an Australian icon, a double-layered biscuit [cookie] with a cream filling and a chocolate coating. I used original (milk chocolate) Tim Tams to make the brownies, but you could also try other flavours.
The recipe is here. I reduced the sugar by a third (as I always try to do) and cut the butter back to 100 grams, but otherwise followed it to the letter. We'll be taking the brownies to our friends' place for dessert tonight and serving them with Kohu Road salted caramel ice cream.