Andrew Coe and Jane Ziegelman, a husband-and-wife team of authors and food historians, host their dinner parties in a broad Brooklyn Heights kitchen designed to resemble a nineteen-thirties schoolroom: red cupboards, wood counters that groan with the accumulated weight of cookbooks. Although Coe and Ziegelman once co-wrote a history of foie gras, their latest project is “A Square Meal: A Culinary History of the Great Depression,” a thick volume that examines a complex decade in American dining.