Pain au Chocolat

Instructions

1. Prepare the dough
   In a large bowl, mix the flour, sugar, salt, and yeast. Gradually add the cold milk and mix until a dough forms. Knead for about 5 minutes until smooth. Shape into a rectangle, wrap in plastic, and refrigerate for 1 hour.
2. Prepare the butter block
   Place the cold butter between two sheets of parchment paper. Using a rolling pin, flatten it into a 7x7 inch square. Keep refrigerated until needed.
3. Laminate the dough
   Roll the chilled dough into a 10x14 inch rectangle. Place the butter block in the center and fold the dough over it like an envelope. Seal the edges. Roll it out to a 10x24 inch rectangle, then fold it in thirds like a letter. Wrap and refrigerate for 30 minutes. Repeat this folding process two more times, chilling for 30 minutes between each fold.
4. Shape the pastries
   Roll the dough into a large rectangle about 12x20 inches and 1/8 inch thick. Cut into 12 rectangles approximately 4x6 inches each. Place chocolate batons or a line of chocolate chips along the shorter edge of each rectangle. Roll the dough over the chocolate, then roll again to form a cylinder with the seam on the bottom.
5. Final proof
   Place the shaped pain au chocolat on parchment-lined baking sheets, leaving space between each pastry. Cover loosely with plastic wrap and let rise at room temperature for 1 hour, or until slightly puffy.
6. Prepare for baking
   Preheat the oven to 400°F (200°C). Mix the beaten egg with 1 tablespoon of water. Gently brush the egg wash over the tops of the pastries, being careful not to deflate them.
7. Bake to perfection
   Bake for 18-20 minutes, until the pastries are golden brown and puffed. Rotate the baking sheets halfway through for even browning.
8. Cool and serve
   Transfer to a wire rack to cool for at least 10 minutes. If desired, dust with powdered sugar before serving. Pain au chocolat is best enjoyed warm while the chocolate is still slightly melted.