Optional: Soak the beans overnight. Rinse the beans under cool, running water. Place in a large bowl or pot and cover with several inches of clean water. Let sit overnight. Drain before cooking.
In a large skillet, heat the oil over medium high heat.
Add the trinity, stir well, and cook until vegetables start to soften, about 3-5 minutes. Stir occasionally to ensure that the vegetables don't stick.
Add the smoked sausage, stir well, and continue to cook until sausage is browned and vegetables are tender, about 5-7 minutes. Continue to stir occasionally to make sure trinity and sausage aren't sticking.
Once done, remove the skillet from heat and transfer the contents to a slow cooker.
Add the water and red beans along with garlic powder, onion powder, bay leaves, and dried thyme. Stir well and place cover on the slow cooker.
Set the slow cooker on low for 10 hours (or 4 hours on high setting). Stir occasionally.
After eight hours (on low setting ) or three hours (on high setting) the beans should be soft. Use the back of a spoon to mash some of the beans against the side of the pot to thicken the beans, for a more creamier style of beans.
Before serving, stir in thinly sliced green onions and the desired amounts of salt and black pepper. Serve over rice and with hot sauce.
If you cannot find pre-chopped trinity in your local grocery store, substitute 2 cups of chopped onions, 1 cup of chopped celery, and 1 cup of chopped bell pepper.
Steps 1 through 3 can be done the day ahead of time, if needed. Store the cooked vegetable and sausage mixture in an air tight container in the refrigerator then just pick up on Step 4 when you’re ready to add everything to the slow cooker.
If you’re strapped for time, skip Steps 1 through 4. Sautéing the trinity and the sausage will add a depth of flavor, but it’s not a requirement. If you skip over to Step 5, add the raw vegetables and sausage to the slow cooker with everything else. Omit the vegetable oil.
Depending on your beans and your slow cooker, the beans may have more water than you’re used to on the stove. The beans will thicken upon standing.
Mash some of the beans on the side of the slow cooker crock if you prefer a creamier style of beans.
The beans can stay in the slow cooker for another couple of hours on the “Warm” setting. Beans will continue to thicken as they warm longer.
Slow Cooker Red Beans & Rice, December 29, 2020 (https://mondaytradition.com/recipe/slow-cooker-red-beans-and-rice/)