Recipe Notes

1. To make the pastry, mix the flours and salt in a large bowl. Toss the butter in the flour mixture until coated; breaking it up a but with your fingertips.
2. Form a well in the center of the dough. Gradually add the water and mix until the flour is slightly moistened.
3. Turn out the dough on a floured surface and knead 8 - 10 times. For into a ball. Flatten the dough into a rectangle.
4. Roll the dough out into a 15-inch square. Fold horizontally into thirds, forming a 15 x 5-inch rectangle. Rotate the dough at a quarter turn, and then fold horizontally into thirds again to for a 5-inch square. Cover with plastic wrap and chill for 30 minutes.
5. Repeat the rolling and folding process twice more, chilling for 30 minutes each time.
6. To make the chocolate filling, melt the butter in a double boiler over medium high heat. Add the chocolate and corn syrup and cook, stirring constantly, until the chocolate is melted. Remove from the heat, stir in the vanilla, and let cool.
7. Preheat the oven for 400°. Line two baking sheets with parchment paper.
8. On a floured surface, roll out the pastry into a 1/8 inch thick, 16 x 15 inch rectangle. Using a pastry wheel or a pizza cutter, cut the dough into six 8 x 5 inch rectangles.
9. Spoon the chocolate filling into the center of each pastry, leaving 1-inch border on the longest side (8 inch) edges. Brush egg white along the clean edges and fold the pastry over to create a rectangle. Press and pinch the edges with your fingertips to seal tightly. Use a knife to score the top with lines to create air vents.
10. Place the croissants on the baking sheets. Brush the tops with egg white and chill for 20 minutes.
11. Bake for 15 minutes. Reduce heat to 350° and rotate the baking sheets. Bake for an additional 10-15 minutes or until golden brown. Cool on the baking sheet for 5 minutes. Transfer to a rack to cool for an additional 15 minutes.