Place 1 pound of red kidney beans in a large bowl and cover with 6 cups of cold water. Add 2 tablespoons of kosher salt and stir until dissolved. Set aside at room temperature for 8 to 16 hours. Drain and rinse.
In a large Dutch oven, heat 1 tablespoon of oil or lard over medium-high heat until shimmering. Add 1 pound of cooked andouille sausage, cut into 1/2-inch disks, and cook, stirring, until lightly browned, about 5 minutes.
Add 1 large finely chopped onion, 1 finely chopped green bell pepper, and 4 finely chopped ribs of celery. Season with salt and cook, stirring, until vegetables have softened and are just starting to brown around the edges, about 8 minutes.
Add 4 minced garlic cloves and cook, stirring, until fragrant, about 45 seconds.
Next, add 1/2 teaspoon to 1 tablespoon of ground cayenne pepper (depending on how hot you like it), 1 teaspoon of ground sage, and a generous 10 to 12 grinds of fresh black pepper. Cook, stirring, until fragrant, about 30 seconds.
Add the kidney beans, a smoked ham hock (if using), 8 ounces of pickled pork shoulder (if using), 4 sprigs of fresh thyme, and 3 bay leaves along with enough water to cover by about 2 inches (roughly 6 to 8 cups). Bring to a boil and reduce to a bare simmer. Cover and cook until beans are completely tender, 1 1/2 to 2 1/2 hours.
Remove lid and continue to cook, stirring occasionally, until liquid has thickened and turned creamy, about 20 minutes. If the pot starts to look dry before the stew turns creamy, add a cup of water and continue simmering. Repeat as necessary until desired level of creaminess is achieved.
Discard bay leaves and thyme stems. Season to taste with hot sauce, a few teaspoons of cider vinegar (if using), and more salt and pepper.
For best texture, let cool and refrigerate overnight. Reheat the next day, adding a little water to loosen to desired consistency.
Serve red beans over steamed white rice.
This recipe comes from Serious Eats.