Set your oven to 400°F (200°C).

On a lightly floured surface, roll out the thawed puff pastry sheets to fit into a 9x13-inch baking dish. Place one sheet in the bottom of the dish, prick it with a fork, and bake for about 15 minutes, or until golden. Allow it to cool.

In a medium saucepan, warm the milk over medium heat until it’s hot but not boiling.

In a large bowl, combine the sugar, cornstarch, salt, egg yolks, and vanilla extract, whisking until smooth.

Slowly pour the heated milk into the egg mixture, whisking continuously to prevent curdling.

Return this mixture to the saucepan and cook over medium heat, stirring constantly, until it thickens and starts to bubble.

Pour the thickened custard over the baked pastry layer in the dish.

Cover the custard with the second sheet of puff pastry, and prick it lightly with a fork.

Bake for another 15 to 20 minutes, or until the top is golden brown.

Allow the dish to cool to room temperature, then chill in the refrigerator for at least 2 hours.

Dust with powdered sugar just before serving. Enjoy!