Using an electric mixer, cream the butter and sugar at medium-high speed until lightened in color.
Add egg and mix until evenly distributed then blend in vanilla extract and salt.
With wooden spoon, combine the flour with the creamed ingredients.
The dough will seem soft but will firm up when refrigerated.
Divide the dough in half, flatten each into a disk shape, and seal in plastic wrap or a plastic bag.
Refrigerate at least 2 hours; preferably, overnight.
To bake, preheat oven to 375 degrees.
To achieve the ideal thickness for your cookie dough, start by liberally dusting the countertop and the dough's surface with flour. This will prevent sticking and make rolling smoother.
Aim for a uniform 1/4 inch thickness across the dough. As you roll, periodically reapply flour as necessary to maintain a non-stick surface.
For added convenience and to avoid distorting the shape of your cookies, consider rolling the dough out directly on parchment paper. This method eliminates the need to transfer the cookies later, ensuring they retain their perfect shape from rolling to baking.
Cut your desired shapes using a cookie cutter (sometimes dipping the cutter in flour or powdered sugar helps.)
It helps to keep the cookies in the refrigerator if the oven is still warming up or if you are working on cutting out more cookies.
Bake at 375 degrees for 8 to 10 minutes. They are done when the edges are very lightly golden. They cookies will continue to harden as they cool.