In a large mixing bowl, combine all-purpose flour, granulated sugar, and salt. In a separate bowl, dissolve active dry yeast in warm milk for about 5 minutes until foamy. Add yeast mixture and melted unsalted butter to dry ingredients, kneading until smooth for 5-7 minutes.

Wrap the dough in plastic wrap and chill in the fridge for 1 hour.

Take cold unsalted butter and place it between two sheets of parchment paper. Flatten it into a 6-inch square.

Roll the chilled dough on a floured surface into a 12-inch square. Place the butter block in the center and fold the corners of the dough over the butter.

Roll this package into a rectangle measuring 8x20 inches, then fold it into thirds. Chill in the fridge for 30 minutes.

Repeat the rolling and folding process for two more turns, refrigerating each time.

Roll the dough out to about 1/4-inch thick. Cut into triangles, approximately 5 inches wide at the base, and roll each triangle to form a croissant shape.

Place on a baking sheet lined with parchment paper and let rise in a warm place for 1.5 to 2 hours.

Preheat oven to 400°F (200°C). Prepare an egg wash by beating an egg and brush the tops of risen croissants.

Bake for 18-22 minutes until deep golden brown. Cool on a wire rack for about 10 minutes.