605 g King Arthur AP Flour
66 g sugar
12 g kosher salt
2 1/4 tsp AD yeast
214 g water, room temperature
120 g whole milk, room temperature
57 g unsalted butter, cut into 1/2-in pieces, chilled
340 g unsalted Kerrygold butter
1 egg yolk
1 tbsp heavy cream
In the bowl of stand mixer with the dough hook, combine the flour, sugar, salt, and yeast; stir to combine. Create a well in the center and pour in the water and milk. Mix on low speed until a tight, smooth dough comes together around the hook, about 5 minutes. Remove the hook and cover the bowl with a damp towel. Set aside for 10 minutes.
Reattach the dough hook and turn the mixer on medium-low speed. Add the butter pieces all at once and continue to mix, scraping down the bowl and hook once or twice, until the dough has formed a very smooth, stretch ball that is not the least bit sticky, 8-10 minutes.
Form the dough into a ball and place seam-side down on a lightly-flowered work surface. Using a sharp knife, cut two deep perpendicular slashs in the dough. Place the dough slashed-side up inside the same mixing bowl, cover with plastic wrap and let rise at room temperature until 1 1/2 times its original size, 45 minutes to 1 hour. Transfer the bowl to the refrigerator and chill for at least 4 hours and up to 12.
As the dough chills, make the butter block: Place the sticks of butter side-by-side in the center of a large sheet of parchment paper, then loosely fold all four sides of the parchment over and use a rolling pin to lightly beat the cold butter into a flat 1/2-in thick layer. Turn over the packet and unwrap, replacing the parchment with a new sheet if needed. Fold the parchment over the butter again, making clean folds in an 8x8 square. Turn the packet over again and roll the pin across the packet, flattening the butter into a thin layer that fills the entire packet, forcing any air out. Transfer to the fridge.
After chilling, remove the dough from the fridge, uncover and transfer to a clean work surface (it will have doubled in size). Deflate the dough with the heel of your hand. Using the four points that formed where you slashed the dough, stretch the dough outward and flatten into a rough square measuring no more than 8 inches on one side. Place 2 pieces of plastic wrap on the work surface perpendicular to each other and place the dough on top. Wrap the dough rectangle, maintaining the squared-off edges, then roll your pin over top as you did for the butter, forcing the dough to fill the plastic and form an 8-inch square with straight sides and right angles. Freeze for 20 minutes.
Remove the butter from the fridge and the dough from the freezer. Set aside the butter. Unwrap the dough and place on a lightly-flowered surface. Roll the dough, dusting with flour if necessary, until 16 inches long, maintaining a width of 8 inches (barely wider than the butter block). With a pastry brush, brush off any flour from the surface of the dough and make sure none sticks to the surface.
You're going to enclose the butter block in the dough and roll them out together. To ensure they do so evenly, they should have the same firmness, with the dough being slightly colder than the butter. The butter should be chilled but be able to bend without breaking. Unwrap the butter so just the top is exposed, then use the parchment paper to carefully invert the block in the center of the dough rectangle, ensuring all sides are parallel. Press the butter gently into the dough and peel off the parchment. You should have a block of butter with overhanging dough on two opposite sides and a thin border of dough aong the other two.
Grasp the overhanging dough on one side and bring it over the butter toward the center, then repeat with the other side of the dough, enclosing the butter. You don't need the dough to overlap, but you want the two sides to meet, so stretch it if necessary, and pinch the dough together along all seams so no butter peaks out anywhere. Life the whole block and dust a bit of flour underneath, then rotate the dough 90 degrees so the center seam is oriented vertically.
Orient the rolling pin perpendicular to the seam and lightly beat the dough all along the surface to lengthen and flatten. Roll out the dough lengthwise along the seam into a 24-in long, 1/4-in thick narrow slab, lightly dusting underneath and over top with flour as needed. It's OK if the shorter sides round a bit - you're going to trim them.
Use a knife or pastry wheel to trim the shorter ends where the butter doesn't fully extend to be perfect, straight sides. Maintaining the rectangular shape at this stage will lead to the most consistent and even lamination. Any bubbles should be popped.
Dust any flour off the dough's surface. Grasp the short side of the rectangle farther from you and fold it toward the midline of the dough slab, aligning the sides. Press gently so the dough adheres to itself. Repeat with the other side of the dough, leaving an 1/8-in gap where the ends meet in the middle. Now, fold the entire slab in half crosswise along the gap in the center. You should now have a rectangular packet of dough, called a "book," that's four layers thick.
Wrap the book tightly in the reserved plastic. If it is ticker than about 1 1/2 inches, or if its lost some of its rectangularity, roll over the plastic-wrapped dough to flatten and reshape it. Freeze the book for 15 minutes then refrigerate for 1 hour.
Let the dough sit at room temperature for about 5 minutes. Unwrap and place on a lightly floured surface. Beat the dough and roll out as before (step 10) into another long, narrow 3/8-in thick slab. It should be nice and relaxed and extend easily. Dust off any excess flour.
Fold the dough in thirds like a letter, bringing the top third of the slab down and over the center third. Press gently so the layers adhere. Wrap in plastic and freeze for 15 minutes, then refrigerate for 1 hour.
Let the dough sit at room temperature for about 5 minutes, then unwrap and place on a lightly floured surface. beat the dough and roll out as before, but into a 14x17 in slab (15x16 for pain au chocolat, or 24x10, then cut in half to two 12x10 slabs for mini croissants). The dough will start to spring back, but try to get it as close to those dimensions as possible. Brush off any excess flour, wrap tightly in plastic, and slide onto a baking sheet or cutting board. Freeze for 20 minutes, then chill overnight.
Five hours before serving, bring a skillet of water to a simmer over medium-high heat. Transfer the skillet to the floor of the oven and close the door. As the steam releases into the oven, line two baking sheets with parchment paper. Let the dough sit at room temperature for 5 minutes. Unwrap, place on very lightly floured surface, and roll out to the correct dimensions once again. Very thoroughly brush off any excess flour. Use a wheel cutter or long knife and ruler to cut the shorter sides, trimming any irregular edges, creating a rectangle exactly 16 inches long (11.5 for mini croissants), then cut into four 4x14 inch rectangles (or 2x11.5 for mini croissants).
Separate the rectangles, then use the ruler and wheel to slice a straight line from opposite corners of one rectangle to form two long, equal triangles. Repeat. Trim the short side of each triangle at a slight angle to make them into isosceles triangles.
Working one triangle at a time, grasp the two corners of the shorter end, the base of the crescent, and tug gently outward to widen the base. Then tug the tail of the crescent to elongate slightly. Starting at the base, snugly roll up the dough and applying light pressure. Place the crescent on one of the parchment-lined baking sheets, resting on the point. If the dough gets too soft, wrap the triangles and freeze for a few minutes. Cover baking sheets very loosely with plastic wrap.
Place the baking sheets inside the oven and let the croissants proof until they're about doubled in size and extremely puffy, 2-2 1/2 hours. Do not rush this process.
Remove the baking sheets and uncover. Transfer sheets to refrigerator and chill for 20 minutes while you heat the oven. Remove the skillet from the oven and heat to 375 degrees.
In a small bowl, stir the yolk and heavy cream until streak-free. Using a pastry brush, gently brush the smooth surfaces of each crescent with the yolk and cream mixture. Avoid the cut sides with exposed layers.
Bake for 20 minutes (less for mini croissants, check at 10 minutes), rotating at 10 minutes. Remove from oven and let cool completely.