Next, take a little lemon zest off a lemon and add it. To get zest-only, rub the lemon on the tiny holes of a box grater. Finally, the dough needs pure vanilla extract, the more fragrant the better. When you start beating again, the batter will turn very yellow and loose, but it won't be that way for long. If you're tempted to leave out the salt, don't, unless you like flat-tasting cookies.
Salt is so important for bringing out the flavors in the ingredients already discussed.
At this juncture, you can put the mixer away. All you'll need to do from here out is stir. Because hard beating develops the gluten in flour, which will make your cookies tough. Stir only until the dough is mealy and all the flour is absorbed. Your cookies will be nice and tender.