Beat butter, granulated sugar, brown sugar and vanilla in a large bowl with mixer until creamy; add eggs, beat well, gradually add flour mixture, mixing well.
Stir in chocolate chips and nuts if desired, drop by rounded teaspoons onto ungreased baking sheet.
Bake 8-10 minutes or until lightly browned, cool slightly; remove from sheet, to wire rack, cool completely.
PAN RECIPE: spread batter in greased 15 x 10 jelly-roll pan, bake at 375°F for 20 minutes or until lightly browned, cool completely; cut into bars.