Preheat oven to 350 degrees F. I always use an oven thermometer. Ovens can, and usually do, heat at a different temperature than what shows on your oven screen. For the best results in any of your baking, I highly recommend using an oven thermometer. Line your baking sheets with parchment paper or silicone baking mats.
In the bowl of a stand mixer with the paddle attachment, add your cool unsalted butter, sugar, and salt. The temperature of the butter and the fact that you use unsalted butter matter here.
Turn your mixer on the lowest speed available. We don't want to incorporate any air into the dough. Air will cause spreading! We just want the sugar to start incorporating into the butter. There will still be some chunks of butter not fully mixed in. That's okay!
You may still see little spots of butter and that's okay!
Add the flour to your wet ingredients.
Once more, turn your mixer on to the lowest setting, and mix until it all comes together. It will to gather onto the paddle and start to clean the sides of the bowl.Turn the mixer off and touch the dough. If you can leave an imprint with your finger without the dough sticking to it, its ready. I live in a humid area, but the amount of flour in the recipe is perfect 9 1/2 times out of 10.
Place your dough on a piece of parchment paper lightly sprinkled with flour. Sprinkle flour on the top of the dough as well.
Using a rolling pin, roll your dough out and cut into the shapes you need.
Place your cut dough onto your parchment paper covered cookie sheet and bake in your preheated oven for 10-14 minutes depending on the size of your cookies.
After removing from the oven, let the cookies set on the cookie sheet for 2-4 minutes.
I usually let my cookies sit in a tupperware container on a paper towel overnight before decorating. This will help grab any extra butter so you don't get that dreaded "butter bleed" after you've spent 2 days decorating them!