# What you'll need:
→ Dough
01 - 2 cups (500g) bread flour
02 - 1/4 cup (60g) granulated sugar
03 - 2 teaspoons (10g) fine sea salt
04 - 1 cup (240ml) whole milk, cold
05 - 1/2 cup (100g) active sourdough starter at 100% hydration
06 - 2 tablespoons (30g) unsalted butter, softened
→ Butter Block
07 - 1 cup plus 2 tablespoons (250g) unsalted butter, cold
→ Egg Wash
08 - 1 large egg
09 - 1 tablespoon whole milk
# Method:
01 - In a large mixing bowl, combine bread flour, granulated sugar, and fine sea salt. Add cold whole milk, active sourdough starter, and softened butter. Mix until just combined, then knead until a smooth, elastic dough forms, approximately 8 minutes.
02 - Shape dough into a rectangle, wrap tightly in plastic wrap, and refrigerate for at least 2 hours.
03 - Place cold butter between two sheets of parchment paper. Pound and roll into a 8 by 6 inch (20 by 15 cm) rectangle. Chill until firm but still pliable.
04 - On a lightly floured surface, roll out dough to a 16 by 8 inch (40 by 20 cm) rectangle. Place butter block on one half, fold dough over, and seal edges firmly.
05 - Turn dough 90 degrees and roll into a 24 by 8 inch (60 by 20 cm) rectangle. Fold into thirds using a letter fold technique, wrap in plastic, and chill for 1 hour.
06 - Repeat the rolling and folding process two more times, chilling for 1 hour between each turn.
07 - After the final fold, wrap dough securely and refrigerate overnight, 8 to 12 hours.
08 - The following morning, roll dough to a 24 by 12 inch (60 by 30 cm) rectangle, approximately 3/16 inch (5mm) thick. Cut into 12 elongated triangles using a sharp knife or pastry cutter.
09 - Starting from the wide end of each triangle, roll tightly toward the point into a crescent shape, tucking the tip underneath. Place shaped croissants on parchment-lined baking sheets.
10 - Cover loosely with a kitchen towel and proof at room temperature until doubled in volume, approximately 2 to 3 hours.
11 - Preheat oven to 400°F (200°C).
12 - Whisk together egg and milk for egg wash. Brush croissants lightly and evenly with the mixture.
13 - Bake 18 to 22 minutes until golden brown and crisp. Cool slightly before serving.