01 -
Preheat oven to 400°F (200°C). Line a baking tray with parchment paper.
02 -
Cut thawed puff pastry into rounds using a circle cutter. Arrange on parchment-lined tray and pierce each round with a fork to prevent excess rising.
03 -
Bake until puffed and golden, about 15-18 minutes. Allow to cool completely before handling.
04 -
In a saucepan, combine milk, sugar, salt, and cornstarch, whisking until well incorporated. Place over medium heat and stir frequently as mixture begins to thicken.
05 -
In a separate bowl, whisk egg yolks. Gradually add a small amount of the hot milk mixture to the yolks while whisking constantly to prevent curdling. Return the tempered egg mixture to the saucepan.
06 -
Continue stirring the custard until smooth and thickened, about 5 minutes. Remove from heat and incorporate butter and vanilla extract until fully melted and integrated.
07 -
Transfer custard to a bowl. Place plastic wrap directly on the surface to prevent skin formation. Refrigerate for 30 minutes until firm.
08 -
Slice cooled pastry rounds horizontally across the middle. Fill bottom halves with chilled custard either by piping or spooning, then place top halves to create sandwiches.
09 -
Just before serving, dust the tops with powdered sugar.