By Charlotte Druckman, The New York Times 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.