For the puff pastry:
In a stand mixer fitted with the paddle attachment, mix the flour and cold butter for a few minutes. Add the water and salt. Mix well; it's normal if the butter isn't fully incorporated into the dough. Shape the dough into a ball and roll it out with a rolling pin. Form a large rectangle and fold the dough like a letter: fold the top third down to the center, then the bottom third up over that. Repeat this folding process at least 3 times.

Once the dough is well rolled out, use a metal ring to cut out circles. Next, prepare the almond cream. Mix the softened butter and sugar together with a spatula until combined. Add the egg, almond flour, and almond extract, and whisk until smooth.

To assemble: Roll out the puff pastry and spread the almond cream on top. Hide a fève (small trinket) in the cream. Moisten the edges of the dough with a little water. Cover with the second sheet of puff pastry. Decorate the top and brush with an egg yolk. Bake for 30 minutes at 350°F (180°C).