01 -
Bring the milk to just below a boil in a small pot. Set aside for later use.
02 -
In a medium pot, beat together the egg yolks, flour, sugar, and vanilla extract until smooth and airy.
03 -
Slowly pour the warm milk into the egg mix while constantly whisking to avoid clumps. Heat it over medium, stirring the entire time, until it thickens and begins a gentle boil. Turn the heat down and cook until it reaches the thickness you prefer.
04 -
Move the custard to a glass bowl, press plastic wrap directly on the surface, and chill completely in the fridge for at least one hour.
05 -
Set the oven to 400°F (200°C). Sprinkle sugar on both sides of the puff pastry. Stretch the sheet gently into a rectangle about 9x12 inches, then slice it lengthwise into 12 strips, each 1 inch wide.
06 -
Take each strip and wind it around a metal horn mold, slightly overlapping the edges. Ensure the ends of the pastry face downward as you place them on a parchment-lined baking sheet.
07 -
Whisk the egg together with a splash of water. Gently apply the egg wash to each pastry, avoiding any spills onto the molds.
08 -
Bake at 400°F (200°C) for 15-20 minutes until golden and flaky. Let them cool for a few minutes before you carefully remove the molds. If they stick, lightly press and twist the metal molds to release them.
09 -
Before you eat, pipe your cold custard into the pastry shells using a piping bag. Sprinkle powdered sugar on top for the finishing touch.