For best results, weigh your flour. 1 cup should be about 4.5 ounces on a scale, so if you use 5 cups you'll use about 22.5 ounces of flour. I used 6 cups, which was 27 ounces. If you don't have a scale, make sure to stir and fluff up your flour before using. If you pack it into the cup, you'll use too much and the cookies might be a little dry.