“Delicious” is the answer. It’s basically a custard pie — the name means “milk pie” — baked in a deep dish, surrounded by filo and soaked with a citrus-scented syrup. Hang on, Joe, that sounds vaguely familiar. Indeed it does, especially if you’re a baklava fan.
But I thought baklava was Middle Eastern or Turkish in origin, isn’t this Greek? Yes and yes, however galaktoboureko represents a melding of those traditions. Greeks have long been makers of pies and custards. It seems that something not entirely dissimilar to a quiche existed in Greece in antiquity.
The key Turkic/Middle Eastern contribution is probably the filo. It’s thought that the idea of stacking fillings between ultra-thin sheets of dough is a tradition that dates back to the ancient Egyptians. That may well be, however it’s the Ottoman Turks who are generally credited with popularizing and disseminating the technique.
The Ottomans occupied Greece for roughly 375 years, from about 1450 to 1821. This is something of a sore point among the Greeks, many of whom consider Ottoman rule to be a period of cultural decline. That may be true too, however the Ottomans likely brought not only filo to Greece but cane sugar and citrus, which are other key components of both baklava and galaktoboureko. So that’s not all bad.