Chef and author Diane Kochilas describes the original bougatsa pastry as "a hand-held phyllo pie made with very thin, very elastic and buttery phyllo that is wrapped and re-wrapped around spinach, cheese or custard." Estrella's version transforms it from a self-contained pie to an oozing, single-serve dessert, but the original bougatsa has been part of Greece's culinary repertoire for almost 100 years, the result of cultural diffusion from the many groups that have traveled through the region. Kochilas explains, "[Thessaloniki] is a multi-cultural city where the earthy foods of northern Greek farmland co-mingle with the influences of the Greeks of Asia Minor." Refugees from the Ottoman Empire settled in northern Greece in 1922, and as Kochilas says, "[Northern Greek] cuisine is rich with all the spices of the East, and it's an urban cuisine, sophisticated, rich, sometimes influenced by French affectations. Many of the dishes we know as Greek classics came to Greece with them, i.e. moussaka and, yes, bougatsa."