cup walnuts, chopped (I'd add more chocolate chips if you do not include walnuts, optional) (optional) or 1 cup pecans (I'd add more chocolate chips if you do not include pecans) (optional)
In a large bowl, cream together butter and shortening; gradually mix in sugars, creaming thoroughly.
Beat in eggs and vanilla.
Combine flour, baking soda and salt; blend into creamed mixture. Stir in chocolate chips and nuts.
Chill for a few minutes or let stand at cool room temperature for 30 minutes.
Drop by rounded teaspoonfuls onto lightly greased baking sheets.
Flatten slightly and smooth edges to make 1/2-inch thick cookie.
Bake in a 375°F oven for 8-9 minutes or until golden brown around the edges and still slightly under-baked in the centre. Let stand on baking sheet for 5 minutes; remove to racks to let cool completely.