Step 1 First, make the chimichurri by combining all the ingredients together well, then allow to stand for an hour or two for the flavours to meld. The sauce should be pourable, so add more olive oil as necessary.

Step 2 Make sure you have allowed your steak to come up to room temperature before starting to cook. The first stage of cooking can be done on a BBQ set for slow indirect heating, or in a domestic oven. It is with using an accurate meat thermometer (a Meater is ideal) to get the temperature just right. We like to cook Tomahawk medium-rare, to an internal of 52°-54°c, which is low enough to remain nicely pink, but enough to allow the fat (which carries all the flavour) to start to melt and baste the meat from within. 

Step 3 Firstly, season the steak generously, particularly the fat, then cook very gently, at a temperature of around 110°c until the centre of the meat is 40°c (or about 12°c lower than the desired finished temperature). Wrap it in foil to keep warm, while you bring the barbecue up to its highest grilling temperature. 

Step 4 Once the grill is hot, remove the foil and grill the tomahawk for a minute or two on each side until beautifully crusted, then remove from the heat and allow to rest for at least 10 minutes. 

Step 5 Carve the steak into thick slices, drizzle with chimichurri, and serve with chips and salad – or your preferred accompaniments.