At Bondir in Cambridge, a little savory tart represents edible history in many corners of the world. Made with chestnut flour, it has the seductive aromas of roasted nuts, butter, and caramelized cheese, and the round is garnished with a confit of shallots and delicate pieces of puffed amaranth barely larger than the eye of a sewing needle.

Chestnut flour, once favored in ancient Rome, became the staff of life for many Italians during World War II, when they turned the nuts into flour. Amaranth is an Aztec grain that dates at least 8,000 years. Teff, eaten primarily in northeast Africa, and prominently used in Ethiopian and Eritrean cuisine to make the flatbread injera, has been cultivated for thousands of years as well.