Pre-heat oven to 400 degrees.
In the bowl of an electric mixer or in a large bowl with a hand mixer, beat together butter, brown sugar, salt, and baking soda, until fluffy, about 2-3 minutes.
Beat in egg and vanilla. Add flour and mix at low speed until just combined, taking care not to over-mix.
Fold chocolate chips into batter.
Drop ½ teaspoons of dough about an 1.5 inches apart onto un-greased cookie sheets.
Bake for about 5 minutes, until cookies are just starting to turn golden. Transfer cookies to baking racks to cool completely.