Make the Dough

1. Melt the 35 g butter and let it cool slightly.
2. Add the cold water, melted butter, salt, and flour to the bowl of a stand mixer fitted with the dough hook.
3. Mix on medium-low speed for 3–5 minutes, until the dough is smooth and soft. Avoid over-kneading.
4. Shape into a ball and cut a shallow cross on top with a sharp knife.
5. Wrap in plastic wrap and refrigerate for at least 2 hours.

Prepare the Butter Block

1. Place the 200 g butter between two sheets of parchment paper.
2. Pound and roll the butter into an even square using a rolling pin.
3. Refrigerate until firm but still flexible. The butter should bend without cracking.

Lock in the Butter

1. Roll the chilled dough into a square slightly larger than the butter block.
2. Place the butter in the center at an angle and fold the four corners of the dough over it.
3. Pinch the seams to completely seal the butter inside.
4. Gently press with the rolling pin, then roll into an even rectangle about 40 cm (16 inches) long.

First Series of Folds

1. Make a double fold by bringing both ends toward the center, then folding the dough in half like a book.
2. Rotate the dough 90° (a quarter turn) in the same direction, then roll it back into a long rectangle.
3. Make a single fold by folding the dough into thirds like a letter.
4. Wrap and refrigerate for 1½–2 hours.

Second Series of Folds

1. Roll the chilled dough into a long rectangle and make another double fold.
2. Rotate 90°, roll into a rectangle again, then make another single fold.
3. Wrap and refrigerate for another 1½–2 hours.

Final Fold

1. Roll the chilled dough into a long rectangle and make one final single fold.
2. Wrap and refrigerate until ready to use, or use immediately if the dough is still cold and firm.

Folding sequence: Double fold + single fold → chill → double fold + single fold → chill → single fold.