Hi Nigella and team! I can't help but wonder what you mean by bouquet garni in terms of Nigella's turkey brine recipe (Feast, p10). It seems that the recipe asks for everything in a bouquet garni already, which is why I wonder why you include it? Also, I wish you would promote your sweet potato casserole (Feast, p29) more often as its fantastic and a great addition to both the Thanksgiving and Christmas table!
Nigella's turkey brine recipes in both Feast and Christmas (p115) include a bouquet garni, along with other spices and some parsley stalks. Traditionally a bouquet garni is a tied bundle of fresh herbs used to infuse a liquid (such as a stock or brine) with flavour. The bundle usually contains parsley, thyme and bay and then may have other herbs added, for example marjoram, oregano, rosemary and sage are all popular. Sometimes the bundle is wrapped in a few leaves from a leek or wedged between two sticks of celery.
Nigella's brine recipes only include the stalks from a bunch or parsley and not the other herbs, so the bouquet garni adds extra flavour from the additional herbs. You can either make your own bundle of herbs to use in the brine or buy one of the dried varieties that look like little teabags, according to your personal preference.