Preheat the oven to 350 degrees . Using an electric mixer, beat the butter with the granulated and brown sugars until just combined and sandy (do not cream). Mix in the egg until just combined, about 3 seconds. Add the flour, baking soda and salt and mix until just incorporated. Mix in the chocolate chips.
On a large ungreased cookie sheet, drop heaping tablespoonfuls of dough a few inches apart. Bake until just golden around the edges, about 20 minutes. Transfer the cookie sheet to a rack to cool completely.