How to Make It
In a large bowl, whisk together the flour, baking soda, and salt. Set aside.
Using an electric mixer, beat the butter and sugar until smooth. Add the egg and beat until fluffy, about 2 minutes. Beat in the vanilla.
With the mixer on low, gradually add the flour mixture, mixing until just incorporated (the dough will be stiff). Shape into a disk and (unless otherwise specified in an individual recipe) refrigerate, wrapped, for at least 1 hour and up to 3 days.
Make cookies according to directions in the 10 Ideas For Sugar Cookie Dough collection. Alternately, make cutout cookies by doing the following: Heat oven to 350° F. On a floured surface, roll out each disk ¼ inch thick. Cut into shapes and place on parchment-lined baking sheets; refrigerate until firm. Sprinkle with decorating sugar, if using, and bake until just beginning to brown, 12 to 15 minutes.
Store cookies in an airtight container at room temperature for up to 1 week.