Stir together flour, cocoa, baking soda and salt. Cream butter and shortening in large mixer bowl until light. Gradually beat in brown and granulated sugars. Beat in egg and vanilla. Blend in dry ingredients. Stir in peanut butter chips and peanuts. Drop spoonfuls of dough, 2 inches apart, onto ungreased cookie sheets; flatten slightly with back of spoon. Bake in 375F (190 °C) oven for 7 to 8 minutes. Cool on sheets 1 to 2 minutes; remove from sheets and cool completely.