1-First, prepare the dough on Day 1 by combining 600g all-purpose flour, 65g granulated sugar, 12g sea salt, 112g whole milk, 205g room temperature water, 60g active sourdough starter, and optional 1.5g active dry yeast in a stand mixer at low speed for 1 minute. Next, add 56g cold unsalted butter cut into ½-inch pieces and mix for 3-4 minutes until the dough is smooth and elastic, then shape it into a ball, cover, and let it rise at room temperature for 3-6 hours until it’s 1.5 times its original size. Afterward, refrigerate the dough for at least 4 hours or overnight to develop those flavors.

2-Preparing the Butter Block: While the dough rests, prepare the butter block by flattening 340g unsalted butter with 84-86% butterfat into an 8-inch square about ½-inch thick, using a rolling pin between parchment paper. Chill this in the refrigerator until you’re ready for the next step, as keeping everything cold is key to those perfect layers.

3-On Day 2, move to laminating the dough: deflate the dough, roll it into an 8×8-inch square, wrap it, and freeze for 20 minutes to make it easier to handle. Then, roll the dough into a 16×8-inch rectangle, place the chilled butter block in the center, and fold the edges over to fully enclose it. Perform the first fold by rolling the dough to a 24-inch length, folding it into thirds, and then folding again like a book; chill it for 15 minutes in the freezer followed by 1 hour in the refrigerator.

4-Final Shaping and Baking: For the second fold, roll the dough to a 24×8-inch rectangle, fold into thirds, and chill again as before; then pre-shape to 14×17 inches, freeze for 20 minutes, and refrigerate overnight. On Day 3, roll the dough to 17×14 inches, trim to 16×14 inches, and cut into four 4×14-inch strips; slice each strip diagonally into triangles, widen the base to 3 inches, and gently stretch the length before rolling tightly from base to tip to form the croissants.

5-Place them on parchment-lined trays and proof at room temperature for 4-6 hours until doubled in size, or use a proofing box with steam for 2-3 hours. Chill the proofed croissants in the fridge for 20 minutes, preheat your oven to 375°F (190°C), brush the tops with a mixture of 1 egg yolk and 1 tablespoon heavy cream, and bake for 25-30 minutes until deep golden and flaky. Let them cool completely before serving, and remember that keeping the dough and butter cold during laminating is essential for those flaky layers. For more on fermentation benefits, visit a trusted sourdough resource to learn how it enhances nutrition.