Preheat your oven to 400°F (200°C). Line two baking sheets with parchment paper and set them aside.

Cut the thawed puff pastry sheet into three strips along the fold marks. Place these strips on one of the prepared baking sheets and poke a couple of holes in each strip with a fork.

Bake in the preheated oven for about 15 minutes or until they turn golden brown. Allow the baked pastry to cool on a wire rack.

In a medium saucepan, place the milk and bring it to a simmer over medium heat.

While the milk is heating, in a small bowl, whisk together the sugar, cornstarch, and a pinch of salt.

Gradually add the cornstarch mixture to the simmering milk, stirring constantly and cook this mixture for about 6 minutes or until it thickens.

In a separate bowl, beat the egg yolks and then add them to the thickened milk mixture. Cook for an additional 2 minutes, stirring frequently.

Add the vanilla extract and butter to the custard, and remove it from heat. Allow the custard to cool to room temperature and refrigerate until ready to use.

Take one of the cooled puff pastry strips and spread a generous layer of arequipe on top.

Place another puff pastry strip on top of the arequipe layer and repeat this process until you’ve used all the pastry strips, creating layers of puff pastry and creamy arequipe.

Dust the top layer with powdered sugar for an extra touch of sweetness.