OK, I made Fabulous Fudge cake from the non-Hershey's link in my second post above, and it was a hit! The frosting came from the same site; I did a search on "dark chocolate frosting" and chose a cream chees frosting. I doubled the chocolate in both recipes. I also smeared "Hershey's Special Dark" fudge sauce directly on the cake before frosting- I had to transport it 15 miles so didn't do it while hot, as I wanted to frost it when I got there- but it still came out fine. The crowning glory was when the resident baking expert asked me for the recipe!
And now my daughter wants me to do it again for her birthday in Feb! What a compliment!