One last thought on rhubarb cake. When we were camping one time, Mom took a rhubarb cake along to eat. She stored it in the camper’s oven when we were traveling, but forgot it when we got home. A couple weeks later, looking for that metal cake pan, she remembered where she’d left it. I don’t remember what was left of the cake as being a moldy, dried up mess. What I do remember though, after we scraped it out, was that the acid from the rhubarb had eaten holes in the metal pan. Just a word to the wise.