Make the dough: In the bowl of a stand mixer, add all ingredients except the butter and knead for 5 minutes.

Shape the dough into a ball and refrigerate for 1 hour.

Prepare the butter: Place the butter between two sheets of parchment paper and pound it with a rolling pin to form a 8-inch (20 cm) square. Chill for 1 hour.

Roll out the dough into a 8x16-inch (20x40 cm) rectangle. Place the butter in the center, then fold both sides of the dough over the butter to seal it completely.

Make a double fold (book fold), then chill for 1 hour.

Make a single fold, then chill for another hour.

Roll out the dough and cut it into 16 rectangles, each about 3x5 inches (8x12 cm). Place 2 chocolate sticks on each rectangle, spaced slightly apart. Roll up each piece. Brush with egg wash and let rise at room temperature for 3 hours.

Preheat the oven to 350°F (180°C). While the oven heats, brush with egg wash a second time and bake for 25 minutes.