# What You’ll Need:
→ Sourdough Croissant Dough
01 - 3.5 cups bread flour
02 - 0.5 cup active sourdough starter at 100% hydration
03 - 0.75 cup cold whole milk
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 and cut into portions for laminating
→ Filling
09 - 4.25 ounces high-quality dark chocolate, minimum 60% cocoa, cut into 12 batons
# Step-by-Step Guide:
01 - Combine flour, sourdough starter, cold milk, sugar, salt, and softened butter in a large mixing bowl or stand mixer. Mix until a rough dough forms. Knead for 4 to 5 minutes until smooth and slightly elastic. Cover and rest at room temperature for 30 minutes.
02 - Transfer dough to a lightly oiled bowl and cover. Bulk ferment at room temperature for 2 to 3 hours, performing stretch-and-fold techniques 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. Center the butter block and fold dough edges to fully encase it. Roll into a 24 by 8 inch rectangle. Fold into thirds, then chill for 30 minutes. Repeat rolling, folding, and chilling two additional times at 30-minute intervals.
05 - Roll laminated dough to a 24 by 12 inch rectangle approximately 0.16 inch thick. Cut into 12 long triangles with a 4 inch base. Position one chocolate baton at the wide end of each triangle and roll tightly toward the point. Place on parchment-lined baking sheets with tip side down.
06 - Cover loosely and proof at room temperature for 4 to 5 hours until doubled and very puffy. If your kitchen is cool, proof in a warm, draft-free location.
07 - Preheat oven to 400°F. Whisk one egg with 1 tablespoon water and gently brush onto croissants. Bake for 18 to 22 minutes until deep golden brown and crisp.
08 - Transfer croissants to a wire rack and cool for at least 15 minutes before serving.