. . . make buttermilk coffee cake. Which I did, and it was pretty good--but for a simple and basic coffee cake, it's hard to beat the Bisquick version (I have a Martha version that comes close). I'm seeing now that the slice I chose to photograph (I love corner pieces, don't you? Corner brownies rock!) doesn't have NEARLY enough sugar/butter topping on it.
Buttermilk is one of those things that you never have when you need it--at least I don't--but then you buy a carton, use a cup, and then what? So my friend shared her carton with me, and wouldn't you know it? I had trouble finding a recipe I wanted to make that had buttermilk in it!
Here's how you fake buttermilk, apparently . . .