Preheat oven to 350°F (175°C). Line baking sheets with parchment paper or silicone liners.
Using an electric mixer on medium speed, beat the brown sugar, sugar, butter, salt, vanilla, and baking soda until smooth and creamy. Add the egg, and mix well.
Reduce mixer speed to low. Gradually add the flour, mixing just until combined. Stir in the chocolate chips.
Drop the dough by 1-tablespoon portions onto the prepared pan, leaving about 2 inches between the cookies.
Bake, one pan at a time, 10-12 minutes, or until the edges are browned and the tops are golden brown.
Cool on the pan on a wire rack for about 10 minutes or until set enough to handle. Then transfer the cookies to a wire rack to cool completely.
Notes
Recipe slightly adapted from King Arthur Baking. Click here to find their medium rye flour.