The vegetables are nothing fancy, just the Holy Trinity. The Holy Trinity is to Cajun and Creole cooking as the Mirepoix is French cooking. Both mirepoix and the trinity are flavor bases for the cuisines. The trinity consists of onion, celery, and bell pepper. The mirepoix is onions, celery, and carrot. Usually, there is a 2:1 ratio, with the onions being the more significant part. For example, if you have one cup of onion, you would need a half cup of celery and a half cup of carrots or bell pepper.
Now for the seasoning, a bay leaf, salt, and pepper are mandatory. No ifs, ands, or buts! Next are the other spices, such as cayenne pepper, smoked paprika (or liquid smoke), and thyme. Now some say, do not add salt to your beans as they cook because they will never get soft. In the past, it has been my experience adding salt at the start of the cooking process lengthens the cooking time.
All of this simmers in a luxurious vegetable stock. I like Kitchen Basics. There are a few options for cooking vessels: crockpot, in a pot on the stovetop, or an Instant Pot. To honest, I have heard people using their oven on low in lew of a crockpot. One other thing, if you go the stovetop route. Make sure the pot is covered. Using a lid ensures you have plenty of liquid to go over your rice.