01 -
Preheat oven to 400°F. Line two baking trays with parchment paper. Lay out puff pastry sheets and prick all over with a fork to prevent excessive puffing. Bake for 12 to 15 minutes until golden and crisp. Allow to cool fully. Trim one pastry sheet to fit the base of an 8×8-inch baking dish. Reserve the second for the top.
02 -
In a saucepan, combine granulated sugar, cornstarch, and salt. Whisk in egg yolks, then gradually whisk in whole milk and heavy cream until mixture is smooth. Cook over medium heat, whisking constantly, until thickened and gently boiling, about 7 to 10 minutes. Remove from heat. Stir in vanilla extract and butter until glossy. Let cool slightly for 5 to 10 minutes, stirring frequently to prevent a skin.
03 -
Place one cooled pastry sheet in the bottom of the baking dish. Pour warm custard over the pastry and spread evenly. Top with the remaining pastry sheet, pressing gently to adhere. Transfer to refrigerator and chill for at least 4 hours or overnight until well set.
04 -
Before serving, dust the top with powdered sugar. Cut into squares with a sharp knife, wiping the blade between cuts for clean edges. Serve chilled.