Using an electric mixer, beat the butter and sugars until combined and creamy. Scrape the sides and bottom of the bowls, and beat in the egg and vanilla. With the mixer on the lowest speed, add the flour mixture in 3 additions. When it is almost combined, add the mini chocolate chips and continue mixing until evenly combined. Do not over mix.
Press wax paper or plastic wrap on top of the cookie dough and chill for at least 1 hour, until the dough is firm.
Place the cooking racks in the upper and lower thirds of the oven. Preheat the oven to 350 F. Line 2 cookie sheets with parchment or silicone mats.