B, a reader and real-life recipe user, wrote in with some blog-love and some follow-up info about Lisa's oat flour query:
I've used both in the Oatmeal Snickerdoodle recipe (one of my favorite cookies EVER!). I got the oat flour from the bulk bins at Whole Foods and used it the first time I made them. The end result is just as delicious and slightly less...gritty? Maybe? No matter how long I grind my oatmeal I can't get it as fine as the oat flour. However, I've made them half a dozen times since then with ground oatmeal and I have zero complaints about them. They still disappear just as quickly as they did the first time!
Thanks for writing in, B. Wow. That's some high praise for my Oatmeal Snickerdoodles. Thank you so much! And thanks also for adding to the conversation. So there you have it, everyone: Ground oatmeal and milled oat flour are perfectly interchangeable. Feel free to use whichever you have on hand!