Prepare the oven and preheat to 175 degrees C or 350 degrees F.
Line with parchment paper into two baking sheets.
Roll out the puff pastry sheets, then put them onto the prepared baking sheets.
Prick the dough with a fork. Make sure not to pierce the bottom of the dough.
Place a saucepan on the stove and turn the heat to medium.
Add butter, milk, sugar, and vanilla. Stir until well blended. Simmer for a few minutes and bring to a boil.
In a mixing bowl, add water and flour. Whisk until well blended.
Add the slurry into the pan, then stir until well blended.
Add a bit of the hot milk mixture into a bowl with the egg yolks, then whisk until well mixed.
Add yolks into the pan and whisk until well incorporated.
Whisk and cook the mixture for about 30 to 60 seconds or until the texture becomes thick.
Add the custard on top of the puff pastry and spread it evenly.
Add the other pastry over the custard, then press.
Put it inside the fridge to chill for at least 3 to 4 hours.
Sprinkle powdered sugar on top.
Serve and enjoy!
