Custard:

I recommend starting with the custard, since we need it to cool down before using it.

In a deep pan combine milk and half of the sugar and bring to a boil. Reduce heat to medium. In a large bowl, using a mixer beat egg yolks and remaining sugar until pale. Add flour and mix well. Add 1 cup hot milk and carefully mix. Gradually add mixture to the remaining hot milk , constantly mixing, until it thickens (for about 5 minutes). Add butter and vanilla extract, mix well, remove from heat and set a side to cool down.

Horns:

In a bowl of a stand mixer beat eggs with sugar, then add milk and butter. Sift flour with baking powder and salt and combine with liquid ingredients. Knead on low speed for 5 minutes. You can of course mix dough by hand, using a mixer is just a little easier.

Divide dough in two parts. Using a rolling pin roll both parts into rectangles 5 mm thick. (Approximate size of each rectangle should be 20 inches long and 12 inches wide. Cut 3/4" stripes of dough lengthwise, using a pastry or pizza knife. Grease metal horn molds and roll each stripe beginning at the tip of the mold, overlapping the layers slightly to almost cover the mold.

Line baking sheets with parchment paper and preheat oven to 350F. Brush horns with lightly beaten egg whites (optional).

Bake in batches until golden or about 30 minutes. Let them cool for 5 minutes and remove horns from molds. Place on a cooling rack and let them cool completely.

To assemble the custard horns:

Fill a piping bag with custard and pipe it into each pastry horn. You can use round, star or no tip.

Pastry horns need to absorb moisture from the custard and get soft, so I recommend, that they are consumed after 24 hours. Pretty difficult!

I hope you like the recipe! I'll be sharing similar recipe for puff pastry horns in the future.