Preheat your oven to 400°F (200°C). Roll out the puff pastry on a lightly floured surface until it's about 1/8 inch thick. Cut into 3x3 inch squares and place on a baking sheet lined with parchment paper. Bake for 15-20 minutes until golden brown.

In a medium saucepan, combine 4 cups of milk, 1 1/2 cups of sugar, and 3 teaspoons of cornstarch. Heat over medium heat, whisking continuously until smooth and begins to simmer.

In a separate bowl, beat 8 eggs and stir in 2 tablespoons of vanilla extract. Gradually add to the heated milk mixture, whisking constantly. Return to low heat and cook for 8-10 minutes until thick.

Whisk vigorously to remove lumps from the custard, allowing it to cool slightly for about 10 minutes.

Arrange your cooled puff pastry squares on a serving tray and carefully pour the warm custard over each, spreading evenly.

Once the custard layer sets slightly, gently spread 2 cups of whipped cream over the custard.

Refrigerate for at least 4 hours or overnight. Before serving, dust with powdered sugar.