Set the oven temperature to 350o and line two baking sheets and a 9×13-inch baking dish with parchment paper, leaving a 2-inch overhang on each side.

Unroll puff pastry sheets and place them on baking sheets that have been lined with parchment paper. Prick the dough all over with a fork, but don’t poke the bottom.

You can put parchment paper on top of each sheet of puff pastry and then put another baking sheet on top to act as a weight so the puff pastry doesn’t rise.

Put the baking sheets in the oven and bake for 20 to 22 minutes, or until they are golden brown. Take it out of the oven and let cool down all the way.

Use a knife with serrated edges to trim the puff pastry so it fits in a 9×13-inch baking dish if needed. Put one puff pastry sheet.

Mix milk, cream, butter, vanilla, and sugar with a whisk in a medium saucepan over medium heat until small bubbles start to form around the edge of the pan, but before it comes to a boil.

To make a slurry, mix flour and water together with a whisk. Then, whisk the slurry into the hot milk mixture and take the pan off the heat.

Whisk a little of the hot milk mixture into the beaten egg yolks to warm them up. Then, whisk the egg yolks into the rest of the mixture while the saucepan is still off the heat.

Put the pot back on the stove and bring it to a boil. Cook for 30 to 60 seconds, whisking constantly, or until the custard gets thick.

Pour the thickened custard over the puff pastry in a 9×13-inch baking dish, then place the second puff pastry sheet on top. (Cut the sides to fit the dish.) Press down gently so the pastry sticks.

Put the baking dish in the fridge until the custard is set. 3-4 hours.

When you’re ready to serve, sprinkle powdered sugar on top, cut the cake, and serve.