I learned the hard way recently that Jell-o and cookies do not mix. I had found a cute recipe online for cookies shaped like watermelons. Somehow, when reading over the recipe it did not strike me as odd that the flavour and colour came from mixing in Jell-o powder. I followed the recipe, the cookies looked great… but they tasted funny. Not necessarily that bad, just super chewy and under-cooked even when following the recipe. I baked them some more, still no. I think the Jell-o made them super chewy. And maybe it is just the disconnect of eating a cookie that does not look like a cookie?
It is also a messy recipe and the dough gets really sticky, you need to flour every surface and your hands- repeatedly.