Cream together the butter and confectioner's sugar for 3 minutes on medium speed. Scrape the bowl a couple of times during the mixing, it should be smooth. Add in the vanilla extract and beat the mixture on low to incorporate it.
In a separate large bowl whisk together the flour and salt. Add this into the butter mixture and mix together on low speed, scraping down the bowl often, until the dough has come together.
Turn the dough out onto a lightly floured area. Squeeze the dough together just a couple of times so that it is smooth.
Wrap the dough in plastic wrap and chill the dough for 30 minutes.
Preheat oven to 325° F. Line a baking sheet with parchment paper. The cut cookies will need to chill before baking so be sure the baking sheet can fit in your fridge.
Unwrap the chilled dough and use a knife to cut it in half. Rewrap one of the halves and hold it in the fridge. Place the other half on a large piece of parchment paper.
Move the dough to one side of the parchment and fold the other half of the parchment over the top of the dough. Use a rolling pin to roll the dough inside the parchment to a ¼-inch thickness.
(Tip: on a toothpick, measure up from the tip ¼-inch and mark it with a Sharpie. To see if your dough is at ¼-inch thickness, poke the toothpick into the dough and check it against the mark.) If you don't want to use parchment paper you can just lightly flour the work surface and rolling pin.
Use a 2-inch cookie cutter (square, circle, your choice) and cut cookies from the dough. Place the cookies onto the parchment lined baking sheet, leaving about 1 inch between them.
Roll scraps together and continue cutting cookies to fill the baking sheet. Prick the top of each cookie three times with the tines of a fork.
Place the baking sheet into the refrigerator for 15 minutes. If you have unused dough, wrap this in plastic and refrigerate it also, until you're ready to roll and cut the next batch.
After chilling, put the cookies in the oven and bake them for about 18-20 minutes: check them after 18 minutes; bake the cookies only until the edges and tops have very lightly browned.
Remove the cookies from the oven and transfer them to a cooling rack to cool completely. Finish rolling, cutting and baking any additional dough you have left.
The cooled cookies can be stacked and sealed in an airtight container for up to 5 days. This recipe makes about 38 2-inch cookies.
Variation: Pistachio Butter Cookies
After mixing the dry ingredients in with the butter-sugar mixture, mix in ⅓ cup of chopped, salted pistachios.
Variation: Lemon Butter Cookies
Reduce the vanilla extract to 1 teaspoon and add to this 2 teaspoons of lemon juice. After mixing the dry ingredients in with the butter-sugar mixture, mix in 1 ½ tablespoons of lemon zest.
Use the best quality butter you can afford here. The butter flavor really shines in these cookies, and it's worth using the good stuff.
This recipe has two chilling times: the first one helps the dough firm up to make it easier to roll out and cut. The second chill helps to keep the cookies from spreading too much while baking. These chills are important so be sure to include them!
The yields listed in the recipe below is based on a cookie cutter that's about 2-inches. Using smaller or larger cutters will change the number of cookies you get.