Put the flour on the paste-board and make a hole in the middle, in which you put the butter, sugar, eggs, salt, and rum. Mix and knead to a rather stiff dough with cold water. Spread it and roll it down to a thickness of about one-eighth of an inch. Glaze it with egg, dust with sugar and bake in a rather quick oven. When cold, cut it in two, spread some compote of peaches or of apricots on one half, put the other half over it, cut in pieces according to fancy, and serve.