1-First, prepare the custard cream: Heat the milk until it’s hot but not boiling. In a separate pan, whisk together 3 egg yolks, 1/2 cup (100 grams) sugar, 1 teaspoon vanilla extract, and 3 tablespoons (30 grams) all-purpose flour until the mixture is light and fluffy. Gradually add the hot milk while whisking to avoid lumps, then cook over medium heat, stirring continuously until it boils and thickens. Reduce the heat and cook for a few more minutes until it reaches the desired thickness. Transfer the cream to a glass bowl, cover with plastic wrap, and refrigerate for at least one hour.

2-Next, preheat your oven to 400°F (200°C). Sprinkle 1/4 cup (50 grams) sugar on a counter and on the defrosted puff pastry sheet (about 8 ounces, 225 grams). Roll the pastry into a 9 by 12-inch rectangle and cut it into 12 strips, each about 1 inch wide.

3-Wrap each strip around a conical horn mold, overlapping by half the length, and place the cones seam side down on a parchment-lined baking sheet.

4-Beat 1 egg with a little water and brush it lightly on the cones, making sure to avoid the mold. Bake for 15-20 minutes until golden, then let them cool and carefully remove from the molds.

5-Finally, fill the shells with the chilled custard cream using a piping bag and dust with powdered sugar before serving. The total preparation time is about 20 minutes, with 25 minutes for cooking and at least 1 hour of refrigeration, adding up to around 1 hour and 45 minutes.