Prepare a square 8 or 9 inch tin with baking paper. Leave a little excess so that you'll be able to lift it out using the paper at the end.
Make the choc chip cookie mix into dough as described on the packet.
Once made into dough, spread it in your baking tin all the way to the edges. I used my fingers to push it carefully into a nice and flat, even layer. Try to get it as even as possible.
Place it to chill in the fridge for 30 minutes or the freezer for about 15 minutes whilst you make your brownie mix.
Make your brownie mix as per the instructions. Fold in some additional white chocolate chips once it's looking nice and glossy and combined.
Preheat the oven to 160C Fan / 180C.
Once the cookie dough is chilled, place some chocolate covered caramels (or your caramel / chocolate of choice) on top of the cookie layer - as many or as few as you like.
Then pour the brownie mixture on top of it all and spread it to the edges. Try to get this layer really flat and even too.
Cook in the oven for about 30 minutes, or until cooked right through. Sometimes the centre can take a little longer, so make sure you check with a skewer after the cook time is up. I've found on occasions it can take 45 minutes when I've used another oven!
Once cooked allow to cool completely in the tin.
When it's completely cooled, make a quick chocolate ganache. Do this by chopping your chocolate very finely with a shape knife (until almost flake like) and placing it in a bowl.
Heat your double cream in a saucepan until just before boiling point. Then pour over your flakey chocolate. Make sure the cream covers the chocolate and then leave it without stirring for 5 minutes.
After 5 minutes, stir the mixture until it combines and becomes smooth.
Pour the ganache over the top of the now cooled baked brownie/cookie and spread it so it goes to all the sides. Again, get it as flat and even as poss.
Sprinkle any decorations on top whilst the ganache is still wet.
Then place the whole thing in the fridge (in the tin) for at least an hour until the ganache has set.
Remove from the tin and slice into squares.