To make the dough place flour, salt and butter combining using a large knife, cutting through the mixture and gradually adding water into the middle and gathering up the mixture with the knife. When all water has been added and dough comes together continue kneading for 6 more minutes until smooth and soft. If it sticks to your hands add a bit of flour (no more than 1 tsp) and knead in. Cover with a bowl and set aside for 20 minutes.