This is a flat, quiche like tart which originates from the region around Verviers in Belgium. It is also common in Aachen (Aix-la-Chapelle), a German city at the border to Belgium. I had it first when I visited a friend in Aachen and we walked over to a small monastery in Belgium. Basically this is kind of pizza base with a topping of rice pudding. Not overly sweet but totally addicting...