Guest host Melissa Clark of The New York Times heads up a big show this week when we launch a new monthly partnership with America’s Test Kitchen. The premise? Good cooks are not born, they are made. Molly Birnbaum, executive editor of Cook’s Science at America’s Test Kitchen, gives us our first lesson: how to cut an onion. Grocery stores are full of choices, or are they? Journalist Simran Sethi, author ofBread, Wine and Chocolate: The Slow Loss of Foods We Love, weighs in. Matt Goulding of Roads & Kingdoms takes us deep into Japan’s food culture with his new book, Rice, Noodle, Fish. Plus Alex Stupak, author of Tacos, explains how to make tortillas at home, Sam Seneviratne, author of The New Sugar and Spice, talks spices, and Lynne Rossetto Kasper tastes six brands of apple cider vinegar.