Adapted from Baking with Julia
2 1/2 cups flour
1 1/4 cups cake flour
1 tablespoon salt
1 1/4 cups ice water
1 pound very cold, unsalted butter
In a food processor, pulse together dry ingredients to mix. Add water and pulse till dough comes together. Shape dough into a ball and slash the top in a tic-tac-toe pattern with a sharp knife. Wrap dough with a damp towel and refrigerate for 5 minutes.
Place the butter between two sheets of plastic wrap and pound with a rolling pin to form a 1 inch thick square. Unwrap chilled dough and place on flour dusted work surface. Roll into a 10-inch square. Roll out each corner of square to make "ears" or flaps. Place butter in center of dough and fold flaps over butter, stretching to overlap and completely encase butter. You should have a 8 inch square.
Press the rolling pin against top and bottom of square. Then roll out to a length of 24 inches, not worrying about the width of the rectangle. Try to get a very even layer of butter sandwiched between the dough. Keep work surface dusted well with flour, but brush off excess before folding.
To make first "turn," fold the rectangle into thirds: up from the bottom and down from the top. Brush off excess flour. First turn is now complete.
Rotate the dough so that the closed fold is to your left. Repeat the rolling and folding...rolling to a length of 24 inches, then folding into thirds. This is the second turn.
If the dough is oozing butter at this point (mine was!), it is time to chill the dough. Wrap well and put in the refrigerator for 30-60 minutes. After cooling time, make two more turns, return to refrigerator for 30-60 minutes, then make the final two turns. The total number of turns needed is 6. Let puff pastry chill at least an hour before using.
Makes 2 1/2 pounds.