My very favorite cake is a Mayonnaise cake–yes, that’s right, cake made with mayo! 
It’s a chocolate/cocoa batter, with mayo replacing the eggs/oil in the batter. In fact, I made one this past weekend, and it was delicious. I frost it with a mocha frosting. All from scratch, naturally.
My grandmother used to make this cake when I was a young girl; I have not been able to find the original recipe she used, although I’ve been told that it’s in a Hershey cookbook. I use a recipe cobbled off of several found in the 'net. It seems to work for me. The cake is very tasty, but also very rich.
tarragon