Preheat oven to 350F. Line a cookie sheet or spray it with non-stick cooking spray. In a mixing bowl with electric beaters, beat together butter and brown sugar.
Add white sugar and beat together again until well combined. Add the egg and vanilla extract then beat until combined.
To the mixture, add the all-purpose flour, baking soda and salt and beat to combine. Finally, pour in the chocolate chips and beat one final time until they're well dispersed into the cookie dough.
Scoop the cookie dough by the (heaping) tablespoon onto your cookie sheet. There should be enough dough for 12 cookies. Bake for 10-12 minutes until the cookies appear puffy and just barely golden. Be aware not to overbake - I recommend removing from the oven even if they don't appear done - gooey cookies are better than crunchy, over-baked ones!
Let the cookies sit on the cookie sheet for 2-3 minutes after removing from the oven. Using a spatula, transfer them to a wire cooking rack and cool for another 20 minutes (but be sure to enjoy a few fresh out of the oven)! Store in an airtight container.