Authentic Polish Kremówka Papieska: Vanilla Custard Cream Cake

Preheat your oven to 400°F (200°C). Unroll each puff pastry sheet onto a baking sheet lined with parchment paper. Prick thoroughly with a fork to prevent excessive puffing. Bake for 15-20 minutes, or until golden brown and crisp. Let cool completely.

While the pastry cools, prepare the vanilla custard. In a medium saucepan, whisk together 3 cups of whole milk, granulated sugar, and salt over medium heat until the sugar dissolves and the mixture is warm, but not boiling.

In a separate bowl, whisk the remaining 1 cup of whole milk with cornstarch and egg yolks until smooth. Slowly temper the egg yolk mixture into the warm milk in the saucepan, whisking constantly.

Continue to cook the custard over medium heat, stirring constantly with a whisk, for 5-7 minutes, until it thickens considerably and coats the back of a spoon. Remove from heat and stir in the vanilla extract. Pour the custard into a bowl, cover with plastic wrap directly on the surface to prevent a skin from forming, and chill in the refrigerator for at least 30 minutes.

Once the custard is chilled, whip the heavy cream in a separate bowl until stiff peaks form. Gently fold the whipped cream into the cooled vanilla custard until fully combined.

Trim one cooled puff pastry sheet to fit the bottom of a 9x13 inch baking dish. Spread the vanilla cream evenly over the pastry. Carefully place the second puff pastry sheet on top of the cream layer.

Refrigerate the cake for at least 2 hours, or preferably overnight, to allow the layers to set and the flavors to meld. Before serving, dust generously with powdered sugar. Slice into squares and serve cold.

To serve, use a sharp, serrated knife to cut through the crisp pastry layers. The cake is best enjoyed chilled.