Melt the chocolate and butter together in a double boiler. Meanwhile, mix the almond meal, hazelnut meal, sugar, and eggs in a bowl. Add the amaretto if using, then stir in the melted chocolate mixture. Mix until smooth. Transfer the filling to a piping bag.

Roll out the puff pastry on a floured surface. Cut out the first circle and place it on a baking sheet lined with parchment paper. Pipe the filling in a spiral from the center, stopping about 3/4 inch (2 cm) from the edge. Place the fève (charm) near the edge.

Cut out the second circle of pastry. Lightly brush it with the egg yolk, sugar, and milk mixture. Use a knife to score a decorative pattern on top as you like. Place this circle over the first one.

Chill the assembled galette for at least 30 minutes. Preheat your oven to 375°F (190°C). Bake for about 45 minutes.