1Preheat the oven to 375 degrees F (190 degrees C). Sift together the all-purpose flour, cake flour, baking powder and baking soda; set aside.
In a large bowl, cream together the butter, white sugar and brown sugar until smooth. Beat in the eggs and vanilla, until well blended. Gradually stir in the flour mixture. Stir in the chocolate chips by hand using a wooden spoon, stir in walnuts if desired. Drop cookies by rounded tablespoonfuls 2 inches apart onto ungreased cookie sheets.
Bake for 10 to 14 minutes in the preheated oven, until the edges are light brown. Let cookies cool on the baking sheet before removing to wire racks to cool completely.