Gaz Smith’s ultimate T-bone steak with mushroom and tarragon vinaigrette

1 First make the vinaigrette. Heat the vegetable oil and mushrooms together slowly over 10-15 minutes, never boiling, just releasing flavour into the oil and softening the mushrooms. Strain the oil into a jug, and once the mushrooms have cooled, chop them coarsely. Add the rest of the ingredients. We want this dressing to stand up to the beef, so it should taste too strong when you taste it by itself, so adjust the balance if required.

2 Season the steak, which should be at room temperature, with salt and black pepper. A T-bone needs to be fat, so don't be tempted to get a steak for each person, get a whopper one, and cook it slowly, like you would a roast, to a nice medium rare.

3 Wait for the coals to go white, then divide up the barbecue into heat zones. I take the hottest coals and spread them on my "hot zone", this could be 350-plus degrees. This is the area to sear the meat on on. Leave the other half of your grill space as a "slow zone".

4 Sear the steak for four to five minutes on both sides, then cook it for a further seven to 10 minutes in the "slow zone", with the lid on the barbecue.

5 Take the meat off the heat and let it rest for 10 minutes.

6 During this time your coals will be cooling down, so pile them up high so you have a concentrated heat zone again.

7 Give the rested steak a blast of heat again before serving. This is my favourite part, watching those juices caramelise up and getting that perfect char. Don't be scared to give a steak of this size a really good char, the exterior is only the surface, a nice two millimetre char will balance out over the other six centimetres of inner flesh.

8 Char the onion rings on both sides on the barbecue (you can also do this earlier and keep them warm.)

9 Carve the steak and serve with the onion rings, liberally drizzled with the vinaigrette.