Marcus Wareing serves his smoky-sweet barbecued steak in a crunchy baguette, with a homemade herb sauce for company. For this recipe you will need a food processor and a barbecue or large griddle pan.
The best way to make these sandwiches ahead of time is ... or until the sauce is no longer bright green. The steak can be marinated eight hours in advance, but it can also be cooked and stored ...