Prep your veggies: chop the onion, bell pepper, and 2 stalks celery. I like to chop the ends of the celery (so that some of the leaves get chopped also) instead of pulling off the stalks. Whichever way you choose will work!
Heat the oil in a large pot over medium high heat. Once it is hot and shimmering, add the chopped onion, bell pepper, and celery. Saute for 6-8 minutes, until the onions start to become translucent.
Mince 2 tablespoons garlic. In a small bowl, combine 1 and 1/2 teaspoons kosher salt, 1/2 teaspoon cayenne pepper, 1 teaspoon thyme, 3/4 teaspoon sage, 1 tablespoon parsley, 1 teaspoon Cajun seasoning, and 1 tablespoon sugar.
Add the garlic and spices to the pot and saute for 1-2 minutes, until fragrant.
Add about 7 cups of water and 1 pound of rinsed red beans. Add the ham bone or ham hock. Add 2 bay leaves.
Stir it all together over high heat until it comes to a boil. Turn the heat down to a low simmer, so that it is just barely bubbling.
Cover with a lid and keep it at a low simmer for 2 and 1/2 to 3 hours. About halfway through the cooktime, either remove the lid or tilt it so that the beans can vent.
After 2-3 hours, taste the beans. They should be tender and flavorful. If they are at all dry or chalky, keep cooking.
Add another half teaspoon or so of salt, or to taste. Add more Cajun seasoning to taste.
Remove the ham bone and bay leaves. Chop any meat left on the bone and return the meat to the beans. Discard the bone.
Serve with hot rice. See notes for a basic recipe!