Step 1: Prepare the Dough

1. In a large bowl, whisk together the flour, sugar, and yeast.
2. Add the cold milk and mix until the dough comes together.
3. Knead the dough for 8–10 minutes until smooth. Incorporate the salt and softened butter while kneading.
4. Shape into a rectangle, wrap in plastic, and refrigerate for at least 4 hours (or overnight).

Step 2: Prepare the Butter Block

1. Place the cold butter between two sheets of parchment paper.
2. Roll it into a 7×7-inch (18×18 cm) square, about 1/4 inch (6 mm) thick.
3. Refrigerate until firm but pliable.

Step 3: Laminating the Dough

1. Roll out the chilled dough into a 10×10-inch (25×25 cm) square.
2. Place the butter block in the center and fold the dough over it like an envelope.
3. Roll the dough into a 24×10-inch (60×25 cm) rectangle and fold it into thirds (like a letter).
4. Refrigerate for 30 minutes.
5. Repeat this rolling and folding process twice more, chilling in between.

Step 4: Cutting and Shaping the Croissants

1. Roll out the dough into a 20×10-inch (50×25 cm) rectangle.
2. Cut into long triangles (4-inch base, 8-inch height).
3. Gently stretch each triangle and roll tightly from base to tip, forming a crescent shape.
4. Place on a parchment-lined baking sheet, leaving space between each croissant.

Step 5: Proofing the Croissants

1. Cover with a clean kitchen towel and let them proof at 72-75°F (22-24°C) for 2-3 hours.
2. They should become puffy but not deflated when touched.

Step 6: Baking the Croissants

1. Preheat the oven to 375°F (190°C).
2. Lightly brush the croissants with egg wash.
3. Bake for 18–22 minutes, until golden brown and crispy.
4. Transfer to a wire rack to cool for at least 15 minutes before serving.