Chef Erin McKenna has earned legions of fans creating gluten-free and vegan desserts at her shop in New York City's Lower East Side. Erin's company, originally called Babycakes, has been renamed Erin McKenna's Bakery, and now she's sharing some of her wisdom about gluten-free baking in a new cookbook called Bread & Butter. We learned how to make one recipe, a delicious vegan and gluten-free lemon cookie, during a visit to her NYC headquarters.