Preheat oven to 450 degrees. With an electric beater, mix all the ingredients for the frangipane cream just until blended. On a slightly floured cold surface, cut 2 circles the size of dinner plates out of the puff pastry. Put one of them on a baking sheet lined with parchment paper. Brush one inch around the edge of the circle with egg wash (beaten egg yolk). Spread half of the frangipane cream on the center and place the second circle on top matching the edges of the circles. Press all around the edges to glue them together. Press softly in the center to evenly spread the filling. If making 2 galettes use remaining cream and follow the same method for preparation.
Decorate the galette with a fork, press edges together all around-no pricking. With the point of a knife, make any kind of design being careful not to go all the way through the puff pastry. Brush the surface with egg wash being careful no to get any on the sides.
Bake the galette in the center of a preheated 450 degree oven for 15 minutes then 350 degrees for 30 minutes. For the last 5 minutes, sprinkle with powdered sugar and bake until golden brown. Serve warm with gold paper crown on top.
For the tradition of Epiphany in the privacy of your kitchen cut the galette in as many parts as people in the party. In one of them, insert a little ceramic toy (big enough to prevent swallowing). In the old days, they used a dried fava bean, so to this day it is still called "la feve." Everyone picks 1 piece of galette the one who discovers the toy is made the king of the day and wears the crown. He picks a queen by putting the toy in her glass and everyone raises his or her glass and applauds. Same process in reverse if a lady finds the toy. Tradition says that the next party should be at the king's expense.
A viewer or guest of the show, who may not be a professional cook, provided this recipe. It has not been tested for home use.