This holiday season, while you’re baking cookies and cakes, note that line “baking powder” in some recipes. In the final product, it is invisible and tasteless, but what does baking powder do? And how has it shaped American cooking?Food historian Linda Civitello’s new book is “Baking Powder Wars: The Cutthroat Food Fight that Revolutionized Cooking”. Original air date: Dec. 20, 2017.