Frangipane Kings Cake - Galette des rois

This is a traditional French pastry called "Galette des rois". This is one of my favorite dessert. It ressembles another french cake called "Pithiviers" but Pithiviers is filled with almond cream only not frangipane.
We bake this Kings cake to celebrate the Epiphany. Therefore when I was a child we would only have it once a year :(
But now i can make it all year long and you can too!
I've used two disks of ready to bake, pure butter, puff pastry dough. If you use homemade or unrolled stored bought dough, roll it out to 1/4 inch thickness. You can make individual cakes, or a squared shape one if you prefer to.

Ingredients

2 pre-rolled puff pastry sheets

For the pastry cream

half skimmed milk 150g -- 5.3 oz.
half of a vanilla bean or 1 tsp. of vanilla extract
white sugar 30g --1.05 oz.
cornstarch 15g -- 0.53 oz.
2 egg yolks

For the almond cream
1 egg
almond powder 80g -- 2.82 oz.
room temperature butter 70g -- 2.46 oz.
white sugar 80g -- 2.82 oz.
bitter almond flavoring 1 tsp.
cornstarch 15g -- 0.53 oz.

For the egg wash
1 egg
white sugar -- 1 tsp.
water -- 1 tbsp.

Cooking time: 30 to 45 minutes in a oven preheated to 200°C/400°F
The outside of the cake must be golden brown, crispy and flaky.