Instructions

1. In a large mixing bowl, combine the flour, sugar, salt, and yeast.
2. Add the cold butter cubes to the flour mixture. Using your fingers or a pastry cutter, work the butter into the flour until it resembles coarse crumbs.
3. Pour in the cold milk and add the egg. Stir until the dough begins to come together.
4. Transfer the dough to a lightly floured surface. Knead for about 5 minutes until it becomes smooth and elastic.
5. Shape the dough into a ball and place it in a greased bowl. Cover with a clean kitchen towel and let rise in a warm place for about 2 hours, or until it doubles in size.
6. Punch down the dough to release the air. Roll it out into a large rectangle, about 1/4 inch thick.
7. Fold the dough into thirds, like a letter. Turn it 90 degrees and roll it out again into a large rectangle. Fold it into thirds again. Repeat this rolling and folding process two more times.
8. Wrap the dough in plastic wrap and refrigerate for at least 1 hour, or overnight for best results.
9. Preheat the oven to 400°F (200°C).
10. Remove the dough from the refrigerator and roll it out again into a large rectangle, about 1/4 inch thick.
11. Cut the dough into triangles. Starting from the wide end, roll each triangle towards the pointed end to form the croissants.
12. Place the croissants on a parchment-lined baking sheet, leaving some space between them. Cover with a clean kitchen towel and allow them to rise in a warm place for about 30 minutes, or until they have doubled in size.
13. Brush the croissants with the beaten egg for a shiny finish.
14. Bake in the preheated oven for 15-20 minutes, or until the croissants are a beautiful golden brown.
15. Let the croissants cool on a wire rack before serving. Enjoy them warm for the ultimate pleasure.