The Big Fat Crispy Rice Squares in Vegan Cookies Invade Your Cookie Jar have been on my list to try. I made them yesterday, they froze overnight, and I cut them tonight. I made two big mistakes.
First, the recipe called for brown rice cereal. The only thing I could find was Koala Crisps (a kids' cereal) whose main ingredient is organic brown rice flour. When I got it home and opened it, I realized they were sweetened with chocolate flavor. So these ended up turning out really sweet. I still liked them, but they'd have been better with regular puffed rice cereal. The gooey, sweet stuff that holds it all together tastes remarkably like the melted buttery marshmallow goo used in regular rice crispy treats.
Second, I used really cheap, thin aluminum foil to coat the pan. They were so sticky that it was hard to get the foil off the bottom.
They'd have been better if I'd used the right ingredients and used better foil, but these were just yummy enough for me.