1Preheat oven to 375.
In a large bowl, beat the butter and shortening with an electric mixer on high for about thirty seconds. Add brown sugar, sugar, and baking soda. Beat until mixture is combined, scraping the sides of the bowl occasionally. Beat in the eggs and vanilla until combined. Beat in as much of the flour as you can with the mixer. (What I do is detach the beater, add all the flour, and mix it by hand so there is not a giant flour explosion. Just mix it until you can safely turn on your mixer.) Mix in the chocolate chips, and nuts if you wish.
2Drop dough by rounded teaspoons 2 inches apart onto ungreased cookie sheets. Bake in a 375 oven for 8-10 minutes or until edges are lightly browned. My personal secret is when I go to take the pan out, I jiggle it, and if the cookie doesn't move then they are done, even if they look underdone. That's how they are perfect!