Step 1: Prepare the Puff Pastry Base

1. Preheat oven to 375°F (190°C).
2. Brush a 9×13-inch baking pan with melted butter.
3. Roll out the puff pastry on a lightly floured surface.
4. Press the pastry into an even layer at the bottom of the baking pan.
5. Bake for 15-20 minutes, or until golden brown and flaky.
6. Let the pastry cool completely before adding the custard.

Step 2: Make the Vanilla Custard

1. In a medium saucepan, whisk together sugar, flour, egg yolks, and milk until smooth.
2. Cook over medium heat, whisking continuously until the mixture thickens.
3. Remove from heat and stir in vanilla extract.
4. Let the custard cool completely before assembling the cake.

Step 3: Assemble the Layers

1. In a mixing bowl, beat cream cheese until smooth.
2. Fold in the cooled vanilla custard and mix until well combined.
3. Spread the custard mixture evenly over the cooled puff pastry base.
4. Top with a generous layer of whipped cream.

Step 4: Chill & Serve

1. Refrigerate for at least 2 hours before slicing to allow the layers to set.
2. Slice into squares, serve chilled, and enjoy!