Warm the Milk: In a small saucepan, heat the milk over medium-low heat until it’s warm (not boiling).

Prepare the Egg Mixture: In a bowl, whisk together the egg yolks, sugar, vanilla, and flour until light and smooth.

Combine with Milk: Gradually pour the warm milk into the egg mixture while stirring constantly to prevent curdling.

Thicken the Custard: Transfer the mixture back to the saucepan and cook over medium heat, stirring continuously until it thickens to a creamy, custard consistency (about 5-7 minutes).

Chill: Remove from heat, transfer to a bowl, cover with plastic wrap, and refrigerate for about an hour to cool.

Preheat the Oven: Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.

Roll and Cut Puff Pastry: On a lightly sugared surface, roll out the puff pastry to a 9×12-inch rectangle. Cut it into 12 equal strips.

Wrap Pastry on Molds: Take each strip and wrap it around a horn mold, overlapping slightly as you go. Place on the baking sheet seam-side down.

Egg Wash: Brush each pastry horn lightly with beaten egg.

Bake: Bake for 15-20 minutes, or until the pastry is golden brown. Let them cool slightly before removing from the molds.

Fill the Pastry Horns: Once the pastries have cooled, use a piping bag to fill each one with the chilled custard cream.

Garnish: Sprinkle powdered sugar over the tops for a final touch of sweetness.