# What You'll Need:
→ Dough
01 - 2 cups plus 2 tablespoons bread flour
02 - 1/4 cup granulated sugar
03 - 2 teaspoons fine sea salt
04 - 1 cup cold whole milk
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 whole milk
# Directions:
01 - In a large bowl, combine bread flour, sugar, and salt. Add cold milk, sourdough starter, and softened butter. Mix until just combined, then knead until smooth and elastic, approximately 8 minutes.
02 - Shape dough into a rectangle, wrap 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 rectangle. Chill until firm but pliable.
04 - On a lightly floured surface, roll out dough to a 16 by 8 inch rectangle. Position butter block on one half, fold dough over, and seal edges carefully.
05 - Rotate dough 90 degrees and roll into a 24 by 8 inch rectangle. Fold into thirds in a letter fold pattern, wrap, and chill for 1 hour.
06 - Repeat rolling and folding process two additional times, chilling for 1 hour between each turn.
07 - After final fold, wrap dough and refrigerate overnight for 8 to 12 hours.
08 - The following morning, roll chilled dough to a 24 by 12 inch rectangle approximately 1/5 inch thick. Cut into 12 long triangles with sharp knife.
09 - Starting from the wide end of each triangle, roll tightly into a crescent shape, tucking the tip underneath. Arrange on parchment-lined baking sheets.
10 - Cover loosely and allow to proof at room temperature until doubled in size, approximately 2 to 3 hours.
11 - Adjust oven rack to center position and preheat to 400 degrees Fahrenheit.
12 - Whisk together egg and milk. Brush croissants lightly and evenly with egg wash mixture.
13 - Bake for 18 to 22 minutes until golden brown with crisp exterior. Cool briefly before serving.