# What You’ll Need:
→ Sourdough Croissant Dough
01 - 3.5 cups bread flour
02 - 0.5 cup active sourdough starter at 100% hydration
03 - 0.9 cup whole milk, cold
04 - 0.25 cup granulated sugar
05 - 2 teaspoons fine sea salt
06 - 2 tablespoons unsalted butter, softened
07 - 1 large egg for egg wash
→ Butter Layer
08 - 1.75 cups unsalted European-style butter, cold, for laminating
→ Filling
09 - 4.2 ounces high-quality dark chocolate, minimum 60% cocoa, cut into 12 batons
# How to Make It:
01 - In a large bowl or stand mixer, combine flour, sourdough starter, cold milk, sugar, salt, and softened butter. Mix until a rough dough forms. Knead for 4 to 5 minutes until smooth and slightly elastic. Cover and let rest at room temperature for 30 minutes.
02 - Place dough in a lightly oiled bowl, cover, and bulk ferment at room temperature for 2 to 3 hours, performing 2 stretch-and-folds at 1-hour intervals. Refrigerate overnight for 8 to 12 hours.
03 - Place cold butter between two sheets of parchment paper. Pound and roll into an 8 by 8 inch square. Refrigerate until firm.
04 - On a lightly floured surface, roll dough into a 12 by 12 inch square. Place butter block in the center and fold dough over to encase butter. Roll out to a 24 by 8 inch rectangle. Fold into thirds using a letter fold. Chill for 30 minutes. Repeat rolling and folding twice more, chilling 30 minutes between each turn.
05 - Roll dough out to a 24 by 12 inch rectangle, approximately 0.16 inch thick. Cut into 12 long triangles with a base of approximately 4 inches. Place a chocolate baton at the wide end of each triangle, then roll tightly toward the tip. Place on parchment-lined baking sheets, tip side down.
06 - Cover loosely and proof at room temperature for 4 to 5 hours, or until doubled and very puffy. If kitchen is cold, proof in a slightly warm, draft-free location.
07 - Preheat oven to 400°F. Beat egg with 1 tablespoon water and gently brush croissants. Bake for 18 to 22 minutes until deep golden brown and crisp.
08 - Transfer to a wire rack and let cool at least 15 minutes before serving.