Add flour 1 cup at a time. IF YOU ARE GOING TO MAKE COOKIES RIGHT AWAY, ADD 3 1/2 cups flour. If you are going to "chill" the dough, or just wait for another day to make your cookies, STOP AT 3 cups. It will be totally soft and look all wrong, and you will want to ignore me completely and add more flour, but I'm telling you -- DON'T DO IT. Practice self-restraint. You will be glad you did, and I will be proud of you.
Roll out on a lightly floured surface. Bake at 375F for 6 1/2 minutes. (I roll my cookies 3/16" thick.)