Blue the recipe is here on the home bakers thread on BYC. It is an 'antique' Pennsylvania Dutch/German recipe passed down from my paternal grandmother to my mother. Mom always said it was the only good thing she ever gave her. I reminded her about dad and she repeated the statement. Always a funny response.
It's listed as Mom's Sour Cream Chocolate Cake.
And yeah, it's rich but decadent. Some people say it reminds them of a mayonnaise cake but I think the sour cream one is better. I make home made butter cream frosting for it and used white frosting yesterday to cut down on the richness but I've called it Mom's Death by Chocolate cake at times when I use chocolate frosting and shave chocolate on top of it. OMG is that good. Set a glass of cold milk beside a slice and keep the jug close by and you can eat until you lapse into a coma.