Chewy Chocolate Cookies

1 ¼ c butter, softened
2 cups sugar
2 eggs
2 tsp vanilla extract
¾ c cocoa
1 tsp baking soda
½ tsp salt
2 c flour
2 cups chocolate chips or nuts, optional

Cream butter and sugar. Add eggs and vanilla; blend well. Combine flour, cocoa, baking soda and salt. Gradually blend into creamed mixture. Add chocolate chips and nuts. Drop by teaspoonful onto an ungreased cookie sheet. Bake at 350 degrees for 8-9 minutes. (Do not overbake, cookies will be soft. They will puff during baking and flatten during cooling.) Cool on cookie sheet until set, about 1 minute. Remove to rack to cool completely.