Cornetto Italian Butter Croissant

In a large bowl, combine warm milk, yeast, and a tablespoon of sugar. Let it sit for 5-10 minutes until foamy. Add the remaining sugar, one egg, vanilla extract if using, and salt. Gradually add the flour, mixing until a shaggy dough forms. Turn onto a lightly floured surface and knead for about 10 minutes until smooth and elastic. Place the dough in a lightly oiled bowl, cover, and let it rise in a warm place for 1.5 to 2 hours, or until doubled in size.

While the dough rises, prepare your butter block. Place the cold unsalted butter between two sheets of parchment paper. Using a rolling pin, flatten the butter into a 20x20 cm (8x8 inch) square. Ensure the butter is pliable but still cold. Refrigerate until ready to use.

Once the dough has doubled, gently punch it down and roll it out on a lightly floured surface into a rectangle approximately 20x40 cm (8x16 inches). Place the cold butter block on one half of the dough, leaving a small border. Fold the other half of the dough over the butter, sealing the edges. Roll the dough again into a 20x60 cm (8x24 inch) rectangle. Perform a 'letter fold' by folding one-third of the dough over the center, then folding the remaining third over that. Wrap in plastic and refrigerate for 30 minutes.

Take the dough from the refrigerator. Rotate it 90 degrees. Roll it out again into a 20x60 cm (8x24 inch) rectangle and perform another 'letter fold'. Wrap and refrigerate for another 30 minutes. Repeat this process for a third fold. This completes the lamination process, creating the many layers characteristic of Cornetto. After the third fold, refrigerate the dough for at least 1 hour, or up to overnight.

On a lightly floured surface, roll the chilled dough into a large rectangle, about 3-4 mm (1/8 inch) thick. Trim the edges to create a neat rectangle. Cut the dough into long triangles (base approximately 8-10 cm / 3-4 inches). Starting from the wide base, gently roll each triangle towards the pointed tip, forming the Cornetto shape. Bend the ends slightly to create the classic crescent. Place the shaped Cornetti on baking sheets lined with parchment paper.

Whisk the egg yolk with water for the egg wash. Brush the Cornetti lightly with the egg wash. Cover the baking sheets loosely with plastic wrap and let them proof in a warm place for 1.5 to 2 hours, or until visibly puffy and almost doubled in size. Preheat your oven to 190C (375F). Bake the Cornetti for 18-22 minutes, or until golden brown and flaky. Let them cool slightly on a wire rack before serving.