Take the dough from the fridge and place on a lightly floured surface. Roll the dough out to a 10”x15” rectangle. Move the dough frequently to make sure it isn’t sticking. If it seems like it needs it, add a little more flour to your work surface.
Using a sharp knife, or pizza cutter trim the edges of the dough to square them up nicely. Then the long way, cut the dough into 3” strips. After they are cut go back and cut each strip in half, so you have roughly 5 rectangles across and 2 down. The rectangle shape should be roughly 3”x5” each. See picture. Using a ruler does help a lot during this step.
After they are cut out, lay out the stick of chocolate at the bottom of the rectangle (the 3” side). Roll the dough over the chocolate stick and place another, chocolate stick, then continue to roll the chocolate croissant until it is rolled completely. Place on a parchment paper lined baking sheet. The chocolate should be in the center of the dough. Continue with all the chocolate croissants. You may need more than one prepared baking sheet. Make sure to leave plenty of room for them to proof/bake.
Depending on the temperature in your kitchen let the croissants proof for 8-12 hours until puffy. They will jiggle a little when the baking sheet is lightly shaken. Proof in a 69-72 degree area. You don't want your butter to get to soft during the proofing of the croissant.
When they are proofed and puffy preheat your oven to 400 degrees. Take a small bowl and whisk egg white and water together. Using a pastry brush lightly brush a layer of egg white wash on the top of your croissants. Try not to get too much egg on the layers (sides). Bake in the preheated oven for 18-22 minutes or until golden brown.
Remove from the oven and remove immediately from the baking sheet to a wire rack to cool.
Croissants are best enjoyed the first day they are made but you can also store them at room temperature and reheat the leftovers in a 400-degree oven for 5 minutes.
Make sure to try one warm from the oven!