# Needed Ingredients:
→ Dough
01 - 2 cups bread flour
02 - 1/4 cup granulated sugar
03 - 2 teaspoons fine sea salt
04 - 1 cup whole milk, cold
05 - 1/2 cup active sourdough starter at 100% hydration
06 - 2 tablespoons unsalted butter, softened
→ Butter Block
07 - 1 cup plus 2 tablespoons unsalted butter, cold
→ Egg Wash
08 - 1 large egg
09 - 1 tablespoon milk
# Preparation Steps:
01 - In a large bowl, combine bread flour, granulated sugar, and fine sea salt. Add cold milk, sourdough starter, and softened butter. Mix until just combined, then knead until smooth and elastic dough forms, approximately 8 minutes.
02 - Shape dough into a rectangle, wrap tightly in plastic wrap, and refrigerate for at least 2 hours until firm.
03 - Place cold butter between two sheets of parchment paper. Pound and roll into an 8 by 6 inch rectangle. Chill until firm but still pliable.
04 - On a lightly floured surface, roll dough to a 16 by 8 inch rectangle. Position butter block on one half, fold dough over, and seal edges firmly.
05 - Rotate dough 90 degrees and roll into a 24 by 8 inch rectangle. Fold into thirds in a letter-fold pattern, wrap in plastic, and chill for 1 hour.
06 - Repeat the rolling and folding process two additional times, chilling the dough for 1 hour between each turn. After the final fold, wrap dough in plastic and refrigerate overnight for 8 to 12 hours.
07 - The following morning, roll chilled dough to a 24 by 12 inch rectangle approximately 1/5 inch thick. Cut into 12 long triangles using a sharp knife.
08 - Starting from the wide end, roll each triangle tightly into a crescent shape, tucking the pointed tip underneath. Arrange on parchment-lined baking sheets, spacing evenly.
09 - Cover loosely with a clean kitchen towel and allow to proof at room temperature until doubled in volume, approximately 2 to 3 hours.
10 - Preheat oven to 400°F. Whisk together egg and milk to create egg wash. Brush croissants lightly and evenly with the egg wash mixture.
11 - Bake for 18 to 22 minutes until golden brown and crisp throughout. Transfer to a wire rack and cool slightly before serving.