She emphasized the importance of focusing on theory, something she feels most baking cookbooks skip over. Hers begins with “Pastry Theory 101,” which explains the most basic elements of baking, like butter, sugar, gelatin and leaveners, and how they function within recipes. Then she expands into the building blocks of pastry. The chapter on chocolate distinguishes ganache from crémeux; the one on custard, crème anglaise from crème pâtissière.
So while you won’t find a recipe for a lemon meringue pie in her book, you’ll learn how to make a crust in one chapter, lemon curd in another and Italian meringue in a third. Apply all three skills to make the pie you’d like. Beginners who don’t feel up to the challenge of tripartite confections can start with banana cake, rice pudding or those “perfect” cookies.
The cookies initially came from a chef she worked with at a private member’s club, who scribbled the formula on a piece of paper for her. Later, when the recipe went missing, she reverse-engineered them, running countless trials in order to put them on the opening menu at Llewelyn’s in 2017.
Ms. Gill shared the results with her co-workers, asking them which sugar they preferred in the cookies, which shape, which texture, bringing rigor and determination to perfecting the recipe. (That applies to projects beyond the kitchen, too: In 2018, she founded Countertalk, a network that connects and supports hospitality workers, and promotes jobs in healthy work environments.)
She landed on a blend of dark brown and caster (or superfine) sugars, and discovered that resting the dough in the refrigerator yielded a more substantive cookie (as opposed to a thinner, chewier one with its butter seeped out). Rolling the dough into balls right away, as opposed to chilling it first, gave her the gentle domes you like to see in the center of a chocolate chip cookie.
One surprising thing is the omission of vanilla, a given in most chocolate chip cookie recipes, starting with the standard on the Nestlé Toll House bag. Ms. Gill didn’t give it a second thought.
Since vanilla has become so pricey (it’s now the second most expensive spice in the world), she’s stopped adding it to recipes unless she wants to showcase its flavor — in a panna cotta, for instance, where its presence would be heightened. “It was an everyday ingredient, and now it’s not,” she said. “It’s like a special-treat ingredient.”