Important Note: I have made these cookies several times lately and experimented with different amounts of cake flour since there seems to be some confusion over what the correct amount really is. Here is the conclusion that I have drawn. If you are using Cake flour, which I strongly suggest, I would use 4 1/3 cups. I would chill them for at least 2 hours prior to baking. If you must use all-purpose flour, I would use 3 1/2 cups and chill for at least 2 hours. I have made these cookies with 3 1/2 cups cake flour, and if you are making drop cookies without chilling, they spread too thin.
Important Note: I have made these cookies several times lately and experimented with different amounts of cake flour since there seems to be some confusion over what the correct amount really is. Here is the conclusion that I have drawn. If you are using Cake flour, which I strongly suggest, I would use 4 1/3 cups. I would chill them for at least 2 hours prior to baking. If you must use all-purpose flour, I would use 3 1/2 cups and chill for at least 2 hours. I have made these cookies with 3 1/2 cups cake flour, and if you are making drop cookies without chilling, they spread too thin.
Vegetable shortening carries the primary structural burden in these cookies, replacing the water content found in butter with pure, 100 percent fat that prevents excessive gluten development and stops the dough from slumping flat into a greasy puddle on the baking sheet. Achieving the signature soft, pale-golden exterior with delicate surface cracks requires strict adherence to temperature control, specifically utilizing a preheated oven set precisely to 375 degrees Fahrenheit while keeping a watchful eye on the 9 to 10 minute bake time so the edges never turn brown.
Skipping the mandatory two-hour refrigeration window will immediately result in misshapen drops that spread too thin because the fat melts before the flour starches can set. Bakers substituting all-purpose flour for the preferred cake flour must adjust the volume downward to 3 1/2 cups to compensate for higher protein content, whereas cake flour requires 4 1/3 cups to maintain proper structure. Overmixing the dry ingredients into the creamed shortening and sugars will toughen the crumb instantly, so fold them gently on slow speed until just incorporated.
Frosting the cooled cookies with the accompanying buttercream requires keeping the icing at room temperature rather than chilling it, since refrigeration causes the large quantity of confectioners' sugar to harden prematurely into an unspreadable paste that ruins the smooth texture.