01 -
Heat the milk in a saucepan. In a bowl, whisk together egg yolks, sugar, vanilla extract, and flour until light and fluffy. Gradually pour the milk into the egg mixture while stirring constantly. Transfer the mixture back to the saucepan and cook over medium heat, stirring until it thickens into a creamy consistency. Remove from heat, transfer to a bowl, cover, and refrigerate for 1 hour.
02 -
Preheat the oven to 400°F (200°C). Roll out the puff pastry on a sugar-dusted surface to a size of 9x12 inches, then cut into 12 strips. Wrap each strip around a horn mold, overlapping as you go. Place the wrapped pastries on a parchment-lined baking sheet, seam side down. Brush with beaten egg mixed with 1 tablespoon of water. Bake for 15-20 minutes until golden brown. Allow to cool slightly before removing from molds.
03 -
Using a piping bag, fill each cooled pastry horn with the refrigerated custard cream. Sprinkle with powdered sugar before serving.