Prepare the custard cream:

• Warm the milk until hot but not boiling.

• In a medium pan, whisk egg yolks with sugar, vanilla extract, and flour until light and fluffy.

• Gradually add warm milk while whisking to prevent lumps.

• Place the pan over medium heat, stirring continuously until it reaches a gentle boil and thickens.

• Once thickened, pour the cream into a bowl, cover with plastic wrap, and let it cool. Refrigerate for at least one hour.

Prepare the pastry horns:

• Preheat the oven to 400°F (200°C).

• Sprinkle sugar on your work surface and on top of the puff pastry. Roll it out to a 9×12-inch rectangle.

• Cut the pastry into 12 strips, each about 1 inch wide.

• Wrap each strip around a conical horn mold, overlapping the edges slightly.

• Place the wrapped molds seam-side down on a baking sheet lined with parchment paper.

• Beat the egg with a tablespoon of water to create an egg wash. Lightly brush each pastry with the egg wash, avoiding contact with the mold to prevent sticking.

• Bake for 15-20 minutes, or until golden brown.

• Allow the pastries to cool for a few minutes before gently removing them from the molds.

Assemble the cannoncini:

• Once the pastries and custard are cooled, fill each horn with the custard cream using a piping bag or small spoon.

• Dust with powdered sugar before serving.