Preheat your oven to 180ºc/160ºfan and line a 9x9" square tin with parchment paper.
In a large bowl, add the melted butter and sugars and beat until smooth.
Add in the eggs and vanilla and beat again until smooth.
Add in the flour and cornflour and beat until a thick blondie mixture is made.
Add the chocolate chips and Rolos and mix through
Pour the mixture into the tin, and spread. Dollop on the caramel and lightly swirl through the blondie mixture.
Bake the blondies in the oven for 25-30 minutes, or until there is a slight wobble in the middle.
Leave to cool in the tin, or on a wire rack.
As an optional extra, you can 'set' your blondies in the fridge for 2+ hours or so to help with the texture! ENJOY!
Notes
The bake time can vary - please make sure your oven is on the correct setting, and check from 22+minutes and onwards till they are baked! These took 25 minutes in my fan oven.
If they turn out cakey, they are over baked - that's all! Bake for a little less time next time.
One top tip is if they've been in for the 25-30 minutes, and you're still not sure, let them cool outside of the oven fully and then put them in the fridge for at least an hour to 'set'. It can firm them right up!