Preheat oven to 350°F.
Line 2 baking sheets with parchment paper or spray with nonstick spray.
In a medium bowl, sift the flour, baking soda and salt together.
In a separate large bowl, beat together the butter and sugar with an electric mixer until smooth and creamy, about 3 minutes.
Add vanilla and egg and mix on low speed until mixed in.
Gradually add the flour mixture and mix in until just incorporated.
Do not overmix.
Chill dough for about 30 minutes.
Using an ice cream scoop or heaping tablespoon, drop the dough onto the prepared baking sheets, 6 to 8 per pan, depending on what size you are making.
Bake the cookies one baking sheet at a time, until bottoms and edges are lightly browned and the tops feel firm when lightly touched.
Small cookies bake 8-10 minutes. Large cookies bake 10-13 minutes.
Let the cookies cool for 5 minutes on baking sheets, then transfer the cookies to wire racks to cool completely.