Begin by lighting your barbecue.
To make the beer-braised onions, add the chicken stock to a saucepan and add the Douglas fir and onions. Pour in the IPA, cover with cling film and slowly bring to the boil. Reduce the heat and allow to simmer until tender.
Bring a large pan of water to the boil and add the potatoes and a generous sprinkling of sea salt. Cook until just-cooked then drain on a wire rack – this is an important step as they need to be very dry to char properly on the barbecue.
To make the green sauce, add all of the ingredients to a high-powered blender and blitz until vibrant and smooth – you’re looking for a coating consistency. Set aside until ready to serve.
To make the rapeseed oil dressing, whisk the oil and vinegar together and season with salt to taste.
When the onions are tender, carefully slice in half with a sharp knife, cutting through the root.
When all of your components are ready, it’s time to barbecue the bavette. Oil and salt the steak, then place on a hot barbecue (about 300°C), closing the lid to impart a nice smokey flavour. Check back every 2–3 minutes or so to check progress – you want it to be a dark golden colour on the underside, but not blackened. When ready, turn over the bavette and continue to cook.
A few minutes before the bavette is ready, add the onions and potatoes to the barbecue to give them a nice char.
When the beef is ready, remove from the barbecue and allow to rest. Once rested, thinly slice the beef against the grain.