01 - Dissolve yeast in warm milk with 1 teaspoon of sugar. Let stand for 5 minutes until foamy and activated.
02 - Combine flour, remaining sugar, and salt in a large bowl. Add melted butter, egg, and yeast mixture. Stir until dough forms, then knead for 5-8 minutes until smooth and elastic. Shape into a ball, cover, and refrigerate for 1 hour.
03 - Place cold butter between parchment paper sheets. Pound and roll into a 6x6 inch square. Refrigerate until firm.
04 - On a floured surface, roll chilled dough into a 12x12 inch square. Position butter block in the center and fold dough edges over to completely encase. Seal edges tightly.
05 - Roll dough into a 16x8 inch rectangle. Fold into thirds like a letter. Rotate 90 degrees, roll out again, and fold once more. Wrap and chill for 30 minutes.
06 - Repeat the rolling and folding process one additional time. Wrap dough and refrigerate for another 30 minutes to rest.
07 - Roll dough into a 16x10 inch rectangle. Cut into 8 equal triangles. Starting from the wide end, roll each triangle toward the pointed tip to form classic croissant shape.
08 - Arrange croissants on a parchment-lined tray, cover loosely, and let rise in a warm place for 1-2 hours until puffy and doubled in size.
09 - Preheat air fryer to 320°F. Brush risen croissants with beaten egg wash for golden finish.
10 - Place 2-4 croissants in air fryer basket without overcrowding. Cook for 8-10 minutes until deep golden brown and fully cooked. Repeat with remaining batches.