IN THE KITCHEN
Put the steaks in a non-metallic bowl or large sealable sandwich bag. Add all of the marinade ingredients, massage into the meat to distribute the flavour and leave to marinade from 1 hour or ideally overnight, turning the steaks in the marinade a couple of times.
To make the chimichurri put the parsley, oregano, garlic and chilli in a small food processor and whizz until finely chopped (alternatively finely chop by hand on a chopping board).
Mix with the olive oil and vinegar and season with salt and pepper.
ON THE BARBEQUE
Prepare the barbeque with the baffle in the down position set at a hot temperature for grilling (about 250-350°C).
Shake off any excess marinade from the steaks, season with salt and pepper and place on the grill. Cover with the lid and cook for about 3 minutes for a medium finish. Turn and cook for a further 3 minutes, again with the lid closed. Remove from the heat, transfer to a plate and leave to rest. Increase or decrease the cooking time of the steaks depending on you prefer the finish. Reduce by 1 minute each side for rare and increase by 1 minute each side for well done.
Brush the halved chicory in a little olive oil, season with salt and pepper and place on the grill and cook for 3-5 minutes each side, with the lid closed, until softened and charred.
Serve the rested steak with the chimichurri sauce spooned over and the charred chicory on the side.