Pour the flour into a large bowl (or directly onto your work surface). Make a well in the center, then gradually add the cold water and salt. Add the butter, cut into small pieces.

Mix everything with your fingertips (or in a stand mixer) until the dough is smooth and slightly firm, that’s totally normal.

Shape the dough into a ball, score a deep cross on top (this helps it relax evenly), wrap it tightly in plastic wrap, and chill in the fridge for at least 30 minutes, or overnight if you want to prep ahead.

Cut the cold butter into cubes and place them in the center of a large sheet of parchment paper.

Fold the parchment over the butter to form a square envelope, about 8 x 8 inches (20 x 20 cm). Using a rolling pin, gently pound the butter to soften it, then roll it out inside the parchment until it forms a smooth, even square.

Chill for 30 minutes in the fridge, or place in the freezer for 15 minutes if you're short on time.

Take the dough out of the fridge and lightly flour your work surface.

Using your fingers, gently press along the four sections created by the cross, flattening the arms while keeping the center thicker. This helps you shape the dough evenly.

Roll it out into a rectangle, about 16 x 8 inches (40 x 20 cm). Place the cold butter block in the center of the rectangle.

Fold the two sides of dough over the butter to enclose it completely.

Press the edges to seal well.

Give the dough a quarter turn (90°), then roll it out again to a rectangle of the same size, being gentle to avoid breaking the layers.

Fold the dough into thirds, like a letter or a brochure (this is a single fold).

Wrap in plastic wrap and refrigerate for 30 minutes, or place in the freezer for 10 to 15 minutes.

Place the dough in front of you with the same orientation as before, then give it a quarter turn.

Roll it out into a longer rectangle, about 24 x 8 inches (60 x 20 cm).

Now fold one quarter of the dough towards the center, then fold the opposite quarter toward the center so the edges meet.

Finally, fold the entire piece in half like a book — this is a double fold (also called a 'wallet fold').

Wrap again and refrigerate for 30 minutes.

Give the dough a final quarter turn.

Roll it out one last time into a rectangle of about 16 x 8 inches (40 x 20 cm). Perform one more single fold, just like in Step 3.

At this point, you can cut the dough in half to make two standard portions of puff pastry. You can also freeze one half for future use!