Calling your chocolate chip cookie “perfect” is a bold move. But British pastry chef Ravneet Gill had no problem doing it. So far, no one’s contested her claim.

At the end of March, she went Live on Instagram to bake her “perfect chocolate chip cookies,” from her first cookbook, “The Pastry Chef’s Guide: The Secret to Successful Baking Every Time,” which was published by Pavilion in Britain in the spring and arrived in the United States on Sept. 8.

People got to baking and shared their results on Instagram; the photos showing a cookie split in two, with an ideal wet-sand crumb surrounding a glossy pull of viscous molten chocolate. Gill, 29, reposted them all on her account.

Nearly six months later, she’s amassed 43,000 followers and “inadvertently caused a lot of people to start making cookies and cakes,” she said. “It just sort of kick-started a lot of people into realizing that this is so easy.”

Eight years ago, after completing an undergraduate degree in psychology, Gill decided to pursue pastry, her mind set on making “flawless patisserie,” or as she describes it in her book, “the stuff that looks unreal because it’s so gorgeous.” She secured an apprenticeship at a restaurant, picked up work at a chocolate shop and began taking classes at Le Cordon Bleu in London. From there, she writes, she “leapt into kitchen after kitchen.”

IN 2015, Gill started as a pastry chef at St. John, the London institution, where there were no elaborate compositions, garnishes or out-of-season ingredients. In that kitchen, she discovered the flawlessness of a plate of honeyed madeleines served unadorned, straight out of the oven, and of a syrup-drizzled British steamed sponge pudding enhanced with Irish stout. Versions of both recipes are in “The Pastry Chef’s Guide.”

“She is very good at passing on her knowledge and sharing her trade secrets,” said Alcides Gauto, who worked with Gill at the London restaurant Llewelyn’s, via email.

Gill said she wrote the book for home cooks to “understand what it is they were doing and not be scared,” and for chefs “who had more pastry knowledge to get to grips with it.”

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 cremeux; the one on custard, creme anglaise from creme patissiere.

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.

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). And shaping the dough into balls before chilling it 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 Nestle Toll House bag. 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 has 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.”

You won’t miss it. You may even prefer your chocolate chip cookies without vanilla going forward. The result is something that tastes closer to cookie dough — you get the flavor of the raw stuff, but the warmth, structure and caramelization that comes with baking.

“One is never enough,” Gauto confirmed.

“They are the best chocolate-chip cookies, actually, I think I’ve made,” said Felicity Spector, a journalist who tested out some of the cookbook’s recipes. “I’ve made lots of other ones.”

Many would argue that “best” is even better than “perfect.”

PERFECT CHOCOLATE CHIP COOKIES

• 1/2 cup plus 2 tablespoons unsalted butter (1-1/4 sticks), softened
• Scant 3/4 cup (140 grams) dark brown sugar
• 2/3 cup (110 grams) superfine sugar
• 1 large egg
• 1-3/4 cups plus 2 tablespoons (250 grams) all-purpose flour
• 1 teaspoon baking powder
• 3/4 teaspoon baking soda
• 3/4 teaspoon Maldon sea salt (or kosher salt)
• 6 ounces (170 grams) dark, bittersweet chocolate, chopped into large chunks

Cream butter and both sugars together using an electric mixer, handheld electric whisk or a wooden spoon for 1 to 2 minutes, until paler but not fluffy. (Do not mix too long; if beaten until super light and fluffy, cookies will deflate when baking.)

Add egg and beat over medium speed until evenly combined.

In a separate bowl, combine flour, baking powder, baking soda and salt; fold into butter mixture using a spatula, until combined.

Add chopped chocolate and fold into dough until evenly distributed.

Immediately scoop out heaping 1/4-cup portions (about 60 grams), roll into balls and place on 2 baking sheets lined with parchment. Cover with plastic wrap and refrigerate at least 12 hours. (If space is tight, condense them on a single sheet before refrigerating, then redistribute on 2 sheets before baking.)

The next day, heat oven to 350 degrees.

Space dough balls evenly on baking sheets, as they will spread. Bake 13 minutes, until cookies are puffed and golden at edges. Middle should be ever so slightly not-quite set.

Let cool on baking sheet; they will continue firming up. Once cooled, eat! Cookies will keep in an airtight container up to 3 days. Makes 14 cookies.

Nutritional information unavailable.

FREEZING THE DOUGH: The balls of dough will keep for up to 2 days in the fridge or 2 weeks in the freezer. If using frozen dough, allow 15 minutes baking time.