Grilled bread rubbed with garlic and moistened with walnut oil is one sort of aillade. A second is a veal (sometimes lamb) stew with a garlicky tomato sauce. A third is this sauce.
Given how peripatetic cooks from the south-west of France are, it is surprising that it has not travelled with them. The Grigson connection here is that Jane asked me at a party whether I still bothered to use cookbooks. I replied truthfully – there’s no point in trying to fool a bullshit