Place the two cold sticks of butter, straight out of the fridge, on a chopping board or the kitchen platform. Sprinkle ¼ cup of all-purpose flour over it and, using a rolling pin or something heavy, beat the butter until it flattens out quite a bit but is still quite solid.
Pat the edges of the butter to form a square. Place in a container and refrigerate for at least 30 minutes.
In a bowl, place 2 cups of flour, salt and, using enough water, knead into a smooth and pliable dough.
Allow the dough to rest for a few minutes, then roll it out into a square large enough so you can wrap the square of butter in it.
Once you have wrapped the butter, making sure it is well-sealed, then roll out the dough into a rectangle about 7 inches wide and 10 inches long. Do this preferably on a metal baking sheet so you have a cool surface and also so you can easily transfer the dough to the fridge. The rolling might take a little work because the dough can be resistant, but be patient.
Now lift the edges of the rectangle along the long side and fold over one another so you have three layers. Place the sheet with the puff pastry in the fridge and let it stand for at least 15 minutes. Then remove and roll out again and fold again to make three more layers. Repeat four more times.
After you've let the dough stand in the fridge for the last time, divide the puff pastry into two. Freeze half and use the rest for the vegetable puffs.