I’ve seen a lot of variations of the “Trinity”–onion, bell pepper…..and something else. It’s always the “something else” that’s in contention. Sometimes, it’s garlic. Sometimes it’s celery. In a few instances, I’ve seen parsley. Yeah. Frickin’ parsley. Personally, I prefer garlic. I’ve never seen my great-grandmother put celery in anything. Ever. I hate the smell of it. I hate the taste of it. I can’t even stand to feel it in my hands. If celery is a quintessential part of YOUR trinity and the shoe fits, by all means, lace that bitch up and wear it. Just not in my house. I would toss my cookies. Fa real. That being said, I’m not going to state “X cups of trinity” in any recipe. I have found that depending upon what your main ingredient is, there is a delicate balance to maintain between flavors. One recipe might call for more onion. Another may call for more bell pepper or garlic. The trinity is not the end-all tell-all one-size-fits-all seasoning for Cajun cooking (or any other kind of cuisine.) Not to get all Miss Science-y Smartass or anything, but there are different moisture contents for different vegetables, and it’ll mean the difference between a gravy that’s of perfect consistency and one that won’t even stick to your rice and drop straight to the bottom of your plate on it’s way to hell where it belongs. Pay attention and observe while you’re cooking. It’s not a Ronco product, for God’s sake. You can’t just “set it and forget it.”