Preheat your oven to 200°C (gas mark 6).
While waiting for the oven to heat up, beat the butter well in a large bowl to soften. Then add the blond cane sugar and beat again.
Add the almond and hazelnut flours and beat. Add a tablespoon of Guénard Almond Oil. Then add the whole egg to the mixture and mix.
Line a tart pan with a sheet of puff pastry. Carefully spread the mixture over it and hide the figurine inside.
Place in the fridge while you make the egg wash: beat together the egg yolk, a pinch of fleur de sel and a tablespoon of water.
Place the second sheet of puff pastry on top and make a small hole in the middle with a knife. With a pastry brush or spatula, brush the egg wash over the cake. Then, use a knife to delicately cut a decorative pattern on top without piercing the pastry.
Bake the cake for 10 minutes at 200°C, then turn down the temperature to 180°C (gas mark 6) and bake for 30 minutes.
Serve warm or cold.