In a large bowl, mix the flour, salt, sugar, and yeast.
Add cold water and mix until a dough forms. Knead for about 10 minutes until smooth and stretchy.
Shape the dough into a rectangle, wrap it in plastic, and refrigerate for at least 1 hour.
While the dough chills, shape the chilled butter into a square (about 15cm x 15cm). You can do this by placing the butter between two sheets of parchment paper and pounding it gently with a rolling pin.
Refrigerate the butter block until firm.
To begin the lamination process, roll out the chilled dough into a rectangle (about 20cm x 40cm).
Place the butter block in the middle of the dough and fold the dough over the butter, sealing the edges.
Roll out the dough into a long rectangle (about 20cm x 60cm), then fold it into thirds, like a letter. This is the first “turn.”
Wrap the dough in plastic and refrigerate for 30 minutes.
Repeat the rolling, folding, and chilling process two more times (for a total of three turns).
To shape the croissants, roll out the dough into a large rectangle (about 20cm x 110cm). Cut into long triangles.
Roll each triangle up from the wide base to the tip to form croissants. Place the croissants on a baking sheet lined with parchment paper.
Cover the croissants loosely with cling film and let them proof in a warm place until they double in size (about 1 to 2 hours).