In a large mixing bowl, mix flour, yeast, sugar, and salt. Add cold milk and ¾ cup cold water. Stir the ingredients so as to form a rough dough. Add the cold butter slices and gently mix them in. You should still see big chunks. If the dough is too dry, add a little more water (1 tbsp at a time). 4 cups (480 g) all-purpose flour 2 ¼ teaspoon (7 g) 1 packet of instant yeast ⅓ cup (67 g) granulated sugar 2 teaspoons fine sea salt ½ cup (120 ml) cold milk ¾ cup (180 ml) cold water 1 ½ cups (335 g, 3 sticks) cold unsalted butter
On a lightly floured work surface, roll the dough using a rolling pin into a long rectangle (about 10×14 inches). This begins the lamination process that creates those buttery layers. Fold it like a letter: top third down, bottom third up. This completes your first turn. If the butter seems soft, wrap the dough in plastic wrap and refrigerate for 30 minutes.
On a lightly floured work surface, roll the dough using a rolling pin into a long rectangle (about 10×14 inches). This begins the lamination process that creates those buttery layers. Fold it like a letter: top third down, bottom third up. This completes your first turn. If the butter seems soft, wrap the dough in plastic wrap and refrigerate for 30 minutes.
Remove the dough from the refrigerator and roll it again into a 10×14 inch rectangle and complete your second letter fold. Wrap and refrigerate for another 30 minutes.
Repeat the process one more time for your third letter fold, then wrap the dough and refrigerate for at least 1 hour before shaping.
Remove the dough from the refrigerator. Cut the pastry in half using a sharp knife or pizza cutter. Keep one half in the fridge and roll the other half into a long rectangle (about 8×15 inches).
Cut the pastry sheet into triangles with a 5-inch wide base and approximately 8 inches in height. Cut a small ½-inch notch at the base of each triangle. Roll from the wide end to the tip to create the traditional crescent shape.
Note: Gather any dough scraps, gently knead them together, and follow the rolling and shaping process (Steps 2 and 3) again to avoid waste.
Place the shaped croissants on a parchment-lined baking sheet or silicone mat with at least 1 inch between each one and cover them loosely with plastic wrap. Let them rise at room temperature (68-72°F is ideal) until they become noticeably puffy and slightly have increased in size, about 1½ to 2 hours. The croissants should jiggle slightly when the baking sheet is gently shaken.
About 20 minutes before baking, preheat your oven to 400°F (200°C). Mix 1 egg + 1 tbsp water for the egg wash. Gently brush the tops of the croissants with the egg wash being careful not to deflate them. Bake them in the preheated oven for 15 to 20 minutes, until they turn golden brown and flaky. 1 egg+ 1 Tablespoon milk
Let your buttery croissants cool for 10 minutes. Eat them warm or at room temperature. Store any leftovers in an airtight container for the best shelf life.