COOK IT.
Blanch the basil and wild garlic in boiling water for 30 seconds, then remove and plunge into a bowl of iced water.
Place the garlic and chilli, basil and wild garlic into a blender along with the vinegar and olive oil and blend until smooth. Adjust the seasoning with lemon juice and salt.
Trim the flank steak of excess fat and sinew, leaving only a layer of the fat on top. Season with rock salt.
Heat your Charcoal Grill and grill fat-side down over hot coals to render and crisp, then turn the flank steak. The coals will have cooled a little, so finish cooking the flank until the internal temperature reads 52- 55°C (125.6°F - 131°F) on a probe thermometer. Remove and rest for 10 minutes.
Spoon over the chimichurri, then slice the flank to serve. Finish with a sprinkle of rock salt.