01 -
Warm milk until hot (not boiling). Whisk egg yolks with sugar, vanilla and flour until fluffy. Gradually whisk in hot milk. Cook over medium heat, stirring continuously until thickened. Cool and refrigerate for at least 1 hour.
02 -
Preheat oven to 400°F. Roll out puff pastry with sugar to 9x12 inches. Cut into 12 one-inch strips.
03 -
Roll each strip onto horn molds with overlap. Place on lined baking sheet with seam down.
04 -
Beat egg with 1 tablespoon water. Brush pastry carefully, avoiding molds.
05 -
Bake at 400°F for 15-20 minutes until golden. Cool briefly, then gently remove from molds.
06 -
Fill cooled horns with custard using piping bag. Dust with powdered sugar before serving.