Preheat oven to 350 degrees F (175 degrees C). Grease a cookie sheet.
In a medium bowl, cream together the butter, white sugar and brown sugar. Stir in the vanilla and egg. Add flour and baking soda, stir until everything is just combined. Don 't mix too much or the cookies won't be chewy.
Drop dough by tablespoonfuls onto the prepared cookie sheet. Place chocolate chips onto the cookies. Bake for 10 to 12 minutes in the preheated oven. Remove from cookie sheet to cool on wire racks.