i dont know if it would work in a deep dish baker but i was at a party today and a lady there said she always uses the batter bowl to make cakes im the microwave. good luck i would liket he answer to the deep dish baker also

 

Rice Cooker Plus?

If you have the Rice Cooker Plus you could try that (of course, you're not showing off the stoneware, but you're getting a few other products in there). There are some other threads with more info (do a search on Rice Cooker Plus), but basically you make the batter as called for, put it into the cooker, plop in 3-4 scoops of frosting, and microwave for 9 minutes, give or take depending on your microwave. I've done a few cake mixes and all have turned out well.

Good luck!
Diane