Combine flour and salt in a bowl
Cut cold butter into small cubes
Add cold water gradually and mix until dough just comes together
Shape the dough into a rectangle
Wrap and chill the dough
Flatten the butter into a thin square
Roll the dough into a larger rectangle
Place the butter in the center of the dough
Fold the dough over the butter to enclose it
Roll the dough out into a long rectangle
Fold the dough into thirds
Chill the dough
Repeat rolling and folding several times
Chill the dough between turns
Use the finished puff pastry as needed