This traditional cake also known as King Cake is an almond filling surrounded by puff pastry. A toy or bean is dropped into the filling and baked. The lucky person who finds the toy is king or queen for the day.
In a large bowl, mix together almonds and sugar. Add the creamed butter, 2 eggs, rum, and mix well together.
Divide the puff pastry dough in half: roll out each half into a 12-inch (about) circle. Lay 1 pastry round sheet on a (very slightly greased) baking pan. Pour the filling in the middle and spread without reaching the edge. Drop your "feve" in the filling.
Top carefully with the second circle of dough. Press firmly all around (with moist fingers) to seal the "cake." Glaze the surface with the remaining beaten egg yolk. (For a little more control over the color, brush the yolk on roughly halfway through the baking)
With a knife or a fork draw some light curved lines for decoration. Make a few tiny cuts on the top (to let out steam during cooking).
Cook for about 35 to 40 minutes in preheated 400-degree oven. Oven temperatures can vary; Remove when golden. Cool and serve while still warm if possible.