In a large mixing bowl, whisk together all-purpose flour, granulated sugar, and salt.

In a separate bowl, dissolve active dry yeast in warm milk, allowing it to foam for about 5-10 minutes.

Combine both mixtures along with melted unsalted butter. Knead the dough for 3-5 minutes until smooth, then shape into a rectangle, wrap in plastic, and refrigerate for at least 1 hour.

Take the cold unsalted butter and place it between two sheets of parchment paper. Roll the butter into a 6-inch square that is even in thickness, then chill for another 30 minutes.

Remove the chilled dough and roll it out into a 12-inch square.

Place the butter block in the center, folding the corners of the dough over it to encapsulate the butter.

Roll the dough into a long rectangle (about 8x20 inches) and perform the first fold by folding it into thirds. Wrap tightly and refrigerate for 30 minutes.

After chilling, roll the dough into a long rectangle again. Fold it into thirds for a second turn, wrap well, and chill for another 30 minutes.

Roll the final dough into a large rectangle about 1/4 inch thick.

Cut out triangles measuring 5 inches wide at the base and roll each triangle from the wide end to the tip.

Place formed croissants on a parchment-lined baking sheet.

Cover the shaped croissants loosely with a kitchen towel and allow them to rise at room temperature for 1.5 to 2 hours.

Preheat the oven to 400°F (200°C). Brush croissants with egg wash and bake for 18-22 minutes until golden brown.

Let the croissants cool on a wire rack for about 10 minutes before serving.