Make sure the butter is room temperature. Room-temperature butter is best for creaming. Use a 1/4 cup cookie scoop for large cookies.  Allow the cookies to rest and cool on the cookie sheet until they are room temperature. The heat from the tray will continue to slowly cook them without over-drying them. Fold in the chocolate chips and buts by hand. The dough is thick and a mixer may not be up to the task.  Bake the cookies at 300 for a longer time to keep them soft.