I forgot the whipping cream!

I completely forgot to buy the heavy whipping cream so the kids could make butter.  What does butter have to do with cellular respiration, you ask?  Nothing really, but they were learning about fermentation, which got us on milk, cheese, cottage cheese and yogurt, which got me talking about making butter from scratch, so then the kids wanted to do it.  I told them if they brought in the supplies, I would do it.  They brought the marbles and someone brought a tiny container of whipping cream.  I told them I would buy the whipping cream this weekend and we would make it on Monday.  Except I forgot about it.  So, today, they were all excited about making butter.  However, after school, I bought two quarts of whipping cream ($11.00!), so tomorrow I will let them make butter.  I'm even going to take some crackers, so they can eat their butter on crackers and enjoy it.  Am I the best teacher or what?