Krémes, or Hungarian custard slice, is a beloved dessert in Hungary. 

Make the pastry: In a large bowl, whisk together the flour and salt. Cut in the cold butter using a pastry cutter or two knives until the mixture resembles coarse crumbs. Gradually add the ice water, tossing with a fork until the dough just comes together. Form the dough into a disc, wrap in plastic wrap, and refrigerate for at least 30 minutes.

Preheat the oven to 400°F (200°C).

Roll out the pastry: On a lightly floured surface, roll out the dough into a thin rectangle about 1/8-inch thick. Trim the edges to create a neat rectangle. Transfer the dough to a baking sheet lined with parchment paper.

Prick the pastry: Using a fork, prick the dough all over to prevent it from puffing up too much during baking. Bake for 15-20 minutes, or until golden brown.

While the pastry is baking, make the custard: In a medium saucepan, whisk together the egg yolks, sugar, and flour. Gradually whisk in the milk, vanilla extract, and salt. Cook over medium heat, stirring constantly, until the custard thickens and coats the back of a spoon. Remove from the heat and let cool slightly.

Assemble the krémes: Once the pastry is cool, spread a generous layer of custard over it. Top with another layer of pastry and spread the remaining custard on top. Dust with powdered sugar and refrigerate for at least 2 hours, or until the custard has set.

Cut and serve: Use a sharp knife to cut the krémes into squares or rectangles. Serve chilled and enjoy!