I was going to say what Julia said. I would only add that if you roll your dough between parchment paper or plastic wrap, it won't pick up the extra rolling flour--plus, theoretically, if you pop the scraps into the refrigerator after cutting your first batch of cookies, the gluten should relax a bit and make your subsequent cookies less tough/chewy. (I never go that crazy. I just roll and cut shapes twice using flour, then make the remaining scraps into the baker's treats (for me!) To me, the third roll (the ones I keep and eat myself) are noticeably denser and chewier, so I don't want to serve them, anyway. 
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[I'm not a Food Scientist, but for the sake of discussion, I believe the science behind it is that gluten is formed only when water hits your flour in the making of the dough. There is water in your butter. (The oil in the butter also helps to avoid the development of gluten by coating the flour so water cannot get into it. I know that sounds like a Catch 22, but it seems obvious that the gluten formation wins out--especially if you handle (knead) the dough a lot.) That combination of moisture and flour continues to develop the gluten strands in the dough the more you mix and handle it. Gluten is what makes baked things chewy and dense; you don't want it to develop a lot in cookies and pastries--only in breads. So, the less you handle your dough, the lighter and flakier your cookies will be. These are things I have read and observed--as I said, I'm not a Food Scientist.]
It makes perfect sense to me. I read from here (http://www.cakepaperparty.com/...sugar-cookie-recipe/) that using only egg yolks "means there is less water for toughening via gluten development and less puffing and distortion via water-mediated leavening. This also means this dough can be rerolled more times without losing cookie quality. The cookies above were rolled 4 times without becoming tough and overworked".
I will try omitting the egg whites and see how it goes.
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