Line two baking sheets with parchment paper and set aside.
Lightly dust your work surface and the top of your dough with flour. Roll out into a 15 x18-inch (38 x 45 cm) rectangle that is about ¼ inch (1/2 cm) thick. Pull and stretch to form straight edges and sharp corners. Patch any holes where butter may have popped through by dusting them with flour. Brush any excess flour off the dough.
Cut the rectangle in half, creating two 15 x 9-inch (38 x 23 cm) sheets of dough. Using a pizza cutter or bench scraper, cut each piece of dough into three equal strips, the short way (you should now have small 9 x 5-inch/23 x 13 cm rectangles). Then cut each strip in half diagonally, so that you left with 6 long triangles. Repeat with other half of dough.
(At this point, before rolling each long triangle, I gently lift each triangle one by one and flip it over, brushing off all excess flour then move the brushed triangles to the parchment paper-lined baking sheets to roll up)
Beginning at the wide base, roll the triangles up, tugging on the tip to elongate it slightly (dip a finger in water and dampened the tip – about 1 inch), then gently pressing it into the dough.
Place on the prepared baking sheets with the tips tucked under, and curve the ends to form crescent shapes. (Leave space between the croissants to rise and the puff up during baking)
Cover the croissants with damp, clean kitchen towels (I loosely cover each croissant-filled baking sheet with plastic wrap then loosely lay a clean kitchen towel on top of that) and allow to rise at cool room temperature until they have almost doubled in size and feel spongy, about 2 hours.
After the 2 hours, slide the croissants into the refrigerator for 20 minutes while you prepare the dipping solution (I do not do this; my fridge is not big enough and it works perfectly).
Preheat oven to 425°F (220°C), positioning one rack in the upper third of the oven, and one in the lower third (in a small French oven, I bake one baking sheet of croissants at a time).