Chewy Chocolate Cookies

1-1/4 cup butter, softened                             
¾ cup cocoa powder
2 cups sugar                                                  
1 tsp baking soda
2 eggs                                                            
½ tsp salt
2 tsp vanilla                                                   
1 cup finely chopped nuts (optional)
2 cups flour
 
Cream butter and sugar in large mixer bowl.  Add eggs and vanilla; blend well.  Combine flour, cocoa, soda and salt; blend into creamed mixture.  Stir in nuts.  Drop by teaspoonfuls onto ungreased cookie sheet.  Bake at 350º for 8-9 minutes.  Cool on cookie sheet until set, about 1 minute.  Remove to wire rack and cool completely.  Makes about 4-1/2 dozen.