To make the chimichurri, place the whole chilli and onion on a BBQ grill over medium-hot coals and chargrill until soft – about 5 minutes.
Chop the onion and chilli very finely and put it in a bowl with the salt, red grape vinegar, garlic, herbs, olive oil and honey. Season well.
For the steak, prepare a BBQ with charcoal or wood and allow the fire to burn out until you have medium-hot coals.
Season the steak well on both sides then place them directly onto the medium-hot coals.
Cook for 2 minutes on one side (don’t worry if the coals stick to the meat, they will release once the meat has caramelised), then flip over and cook for another 2 minutes for medium-rare.
Remove from the heat, cover with foil and allow the steak to rest for 5 minutes. The internal temperature should be 55°C.