01 -
Preheat your oven to 350°F (175°C). Place each puff pastry sheet on separate baking sheets and bake for 10 minutes until golden brown. Allow to cool completely.
02 -
Pour 3 cups of milk into a heavy-bottomed saucepan and slowly bring to a boil over medium heat.
03 -
In a large bowl, vigorously whisk the egg yolks with granulated sugar until the mixture becomes pale and fluffy.
04 -
Add the flour, vanilla extract, optional rum, salt, and remaining cup of milk to the egg-sugar mixture. Whisk until completely smooth and free of lumps.
05 -
Once the milk reaches a boil, gradually pour the egg mixture into the hot milk, stirring constantly. Continue cooking while stirring until the custard thickens significantly and coats the back of a spoon.
06 -
In a clean bowl, beat the egg whites with an electric mixer until stiff peaks form. Gently fold them into the warm custard mixture to create a light and airy texture.
07 -
Place one cooled puff pastry sheet at the bottom of a 9×13-inch baking dish. Spread the custard evenly over the pastry layer.
08 -
Refrigerate until the custard becomes firm, approximately 1-2 hours.
09 -
When the custard has set, whip the heavy cream with powdered sugar until stiff peaks form. Spread this layer evenly over the chilled custard.
10 -
Cut the second pastry sheet into 15 equal squares and arrange them carefully over the whipped cream layer.
11 -
Return the dish to the refrigerator for an additional 2 hours until completely set.
12 -
Before serving, dust the top with powdered sugar if desired. Cut into 15 squares and serve chilled.