So Marian, I tried your microwave chocolate cake for my friend's b-day yesterday. Used a gluten-free cake mix my mom bought me, so it called for a few extra ingredients along with the sour cream and chocolate chips. Baked it the prerequisite amount of time, poked it, it felt done. Then I re-covered it with the plate and tipped it upside down.
NOT so done! Guess my dinosaur of a microwave requires about 10 minutes more time than suggested. So, with the help of my friends, I put the cake and what batter we could reclaim in a sanitary manner BACK in the bowl and nuked it for another 10 minutes.
May I just say "Messy, but YUMMY!!!"
I'm calling it Erupted Volcano Cake.