Chocolate Croissants (Pain au Chocolat)

Place the flour, sugar, yeast and salt in the bowl of the Cuisinart Precision Master 5.5-Quart Stand Mixer. Whisk them together
480 grams (4 cups, spooned and leveled) bread flour plus extra for dusting, 50 grams (1/4 cup) granulated sugar, 7 grams (2 tsp) instant yeast, 10 grams (2 tsp) fine sea salt
Using the hook attachment, with the mixer at low speed, stream in the water.
300 mL (1 1/4 cup) cool water
Allow the mixer to combine the dough for 2 minutes at low speed and then increase the speed to medium for 5 minutes, until the dough completely peels itself away from the edge of the bowl.
Slightly dust a silpat mat or a parchment paper with flour and stretch the dough out into a rectangular shape. Move it to a baking sheet and cover it completely with plastic wrap. Allow the dough to rest in the refrigerator for at least 4 hours or refrigerate overnight.

Use a large sheet or two small sheets of parchment paper and fold it into an 8x10" rectangle. Slice the butter in half, lengthwise so it's thinner and place it into the folded parchment paper. Use the rolling pin to roll the butter out into the shape of the parchment paper. See photos for reference.
284 grams (1 1/4 cup) unsalted butter slightly chilled
Refrigerate the butter for a few minutes while you roll out the dough. You want the butter to be at a temperature where it's still malleable (bends without breaking) but not greasy. Remove the dough from the fridge and on a lightly floured surface, roll it out to 16x10".
Remove the butter from the fridge when it feels right, about 5-10 minutes, and place it on top of the dough, right in the center so that the 10" length of the butter aligns with the 10" length of the dough. Fold the extra dough over the butter and seal the edges together.
On a lightly floured surface, gently roll the dough back out to 16x10" and fold it into thirds, like the photos. Cover the dough completely with plastic wrap and refrigerate it for 10 minutes. Repeat this process 2 more times and after the last fold, cover the dough again and refrigerate it for 2 hours.

Remove the dough from the fridge and allow it to rest at room temperature for about 15 minutes, so it's not too firm to roll. Gently roll the dough out to about 24x12" and use a knife or a pizza cutter to trim the edges into a perfect rectangle.*
Cut the dough in half, lengthwise and then slice each halve into 8 rectangles. Place the chopped chocolate along one short end of each rectangle and roll them up tightly.
12 oz semi-sweet chocolate chopped

Place 4-6 croissants on a lined baking sheet and cover them completely with plastic wrap. Allow them to proof at room temperature (not super warm, around 70F) for about 2-3 hours.
The croissants are done proofing when you press on it gently and your finger leaves an indent in the dough. They should be slightly larger but not quite doubled in size. If you gently shake the pan, the croissants should wobble a little.

Preheat the oven to 400F (204C) convection (375F/181C conventional). Beat the egg with a fork or a whisk and use a pastry brush to gently egg wash the croissants. I like to go over them twice to give it a generous coating. Bake the croissants for 17-20 minutes until they're slightly darker than golden brown.
1 large egg for egg wash room temperature
If you pick them up, the croissants should not feel heavy, they should feel light and airy. Allow them to cool on the pan for 10-15 minutes before moving them to a cooling rack to cool completely.
Croissants are best served at room temperature on the day they were baked. Store in an airtight container at room temperature for 2-3 days or refrigerate for up to a week.