Preheat oven to 350 degrees. In a large bowl, cream shortening, butter, peanut butter and sugars until blended and fluffy. Add the egg and vanilla and beat well. In a medium bowl, stir the salt, soda and flour. Add to the creamed mixture, beating until thoroughly combined. Fold in the chocolate chips. Drop by rounded teaspoonfuls onto ungreased cookie sheets, 2 inches apart. Flatten slightly with the tines of a fork. Bake for 12 to 15 minutes or until lightly browned. Cool on wire racks. (These cookies freeze very well).