# What You 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 cold unsalted butter
→ Egg Wash
08 - 1 large egg
09 - 1 tablespoon milk
# How to Make:
01 - Combine bread flour, granulated sugar, and fine sea salt in a large mixing bowl. Add cold milk, sourdough starter, and softened butter. Mix until just combined, then knead for approximately 8 minutes until the dough becomes smooth and elastic.
02 - Shape the dough into a rectangle, wrap tightly in plastic wrap, and refrigerate for a minimum of 2 hours.
03 - Place the cold unsalted butter between two sheets of parchment paper. Pound and roll the butter into a 8 by 6 inch rectangle. Refrigerate until the butter becomes firm but still pliable.
04 - Roll out the chilled dough on a lightly floured surface to a 16 by 8 inch rectangle. Position the butter block on one half of the dough, fold the other half over, and seal the edges by pressing with your fingers.
05 - Rotate the dough 90 degrees and roll into a 24 by 8 inch rectangle. Fold into thirds in a letter-fold pattern, wrap in plastic wrap, and refrigerate for 1 hour.
06 - Perform the rolling and folding process two additional times, refrigerating for 1 hour between each turn to maintain proper lamination.
07 - After completing the final fold, wrap the dough and refrigerate overnight for 8 to 12 hours to develop deep sourdough flavor and achieve optimal gluten structure.
08 - Roll the chilled dough into a 24 by 12 inch rectangle approximately 1/5 inch thick. Cut the dough into 12 equal long 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. Arrange the shaped croissants on parchment-lined baking sheets.
10 - Cover the baking sheets loosely with a kitchen towel and allow the croissants to proof at room temperature until doubled in volume, approximately 2 to 3 hours.
11 - Position the oven rack in the middle position and preheat to 400 degrees Fahrenheit.
12 - Whisk together the egg and milk in a small bowl. Using a pastry brush, lightly coat each proofed croissant with the egg wash mixture.
13 - Bake for 18 to 22 minutes until the croissants achieve a deep golden-brown color and crispy texture. Cool briefly before serving.