I get those McCann's five-minute (actually takes more like 10) steel cut oats. They've been around for at least a few years. I've only seen them at Whole Foods and Happy Foods, not at Trader Joe's.
I think if you tried to substitute even the five-minute steel cut oats, you'd have a problem, because the steel-cut oats just take so much longer to cook and have more of a "bite." I've
almost tried substituting when I was hankering for oatmeal cookies though.
Sorry about your cookies. Now I have a Who song going through my head.
"things like being careful with your coriander/ that's what makes the gravy grander" - Sondheim