From the Fannie Farmer Cookbook (which claims these famous cookies--if not this recipe--were created by a Massachusetts housewife in 1929):

Chocolate Chip Cookies

1/4 pound (115 g) (1 stick) butter
1/2 cup dark brown sugar
1/2 cup white sugar
1 egg
3/4 teaspoon vanilla
1 1/8 cups flour
1/2 teaspoon salt
1/2 teaspoon baking soda
1/2 cup chopped nuts (optional; I did not use them)
1 cup semi-sweet chocolate chips

Preheat oven to 375 (190 C). Grease cookie sheets. Cream the butter, then gradually add the two sugars and beat until light and smooth. Beat in the egg and vanilla. Mix the flour, salt and soda together and add to first mixture, blending well. Stir in nuts and chips. Drop by teaspoonfuls one inch apart onto cookie sheets and bake for 8-10 minutes until lightly browned.

I found these to be best after they had cooled for several hours.