You can find almond meal at Trader Joes or grind your own in a Cuisinart. For the latter, weigh out whole, unblanched almonds and roast them for about 10 minutes in a 350°oven.
Allow to cool completely, then transfer to a Cuisinart. Add 2-3 T sugar (subtracting from the amount you'd cream with the butter) to the Cuisinart and grind the almonds. Adding the sugar helps keep the almonds from turning into a butter.
Cream butter until it softens a bit. Add sugar and cream until light and fluffy.
Add the egg, mixing well until incorporated.
Add the rum and almond extract.
Add the almond meal, mixing well until incorporated.
Assembling the Galette
Preheat oven to 375°
Unfold thawed puff pastries and using a pie pan as a template cut into two circles (if using homemade puff pastry, roll it out to a thickness of 3mm and about 10 inches in diameter). Make a few cuts in the middle of one of the circles to allow steam to escape while baking.
Lay one circle on parchment paper and spread frangipane in the middle – Leave one inch around the edges of the dough.
Place a dried fava bean or ceramic figure in the frangipane.
Using the egg yolk, brush the edges of the dough.
Place the other dough circle on top and seal the edges very tight
Make a quick egg wash with the remaining egg yolk and 2-3 T milk. Brush top with egg wash, being careful not to let egg wash run over the sides or it will disrupt the puff pastry from showcasing its trademark laminations.
Bake for about 30 min or until the top and edges are nicely browned
Allow to rest for at least 10 minutes before cutting into it.