Preheat the oven at 180 degrees Celsius.
Mix the butter with a fork.
Grate the almond paste and mix with the butter.
Add the sugar and 1 egg and mix.
Add the hazelnut flower and mix together.
Take away the edges of an round baking form.
Cut the Puff pastry in half and place one half over the bottom of the baking form.
Place the filling on top of the puff pastry, make it round as a cake.
Place a hazelnut or a porcelain figure some where in the filling so it's hidden.
Roll in the puff pastry toward the cake, this way you will have a nice edge around your cake.
Whisk an egg and brush the cake all over.
Make nice imprints on the cake.
Place the cake in the oven for 45 minutes.
Take it out and let it cool down.
Before serving make sure to cut the cake in cake pieces. This way no one can cheat and try to find the hazelnut in the cake.