1. Preheat your oven to 375°F or prepare a crockpot for slow cooking.
2. Peel and cut potatoes into uniform chunks for even cooking. Dice fresh green beans, trimming and halving them, or ensure frozen beans are thoroughly thawed.
3. Cook sausage in a skillet until fully browned or prepare crispy bacon for later use.
4. Slice or finely mince onions and garlic for added flavor.
5. Mix potatoes, green beans, sausage, onions, and garlic in a large mixing bowl. Season with garlic powder, onion powder, creole seasoning, thyme, salt, and black pepper. Toss until all ingredients are well-coated.
6. Prepare the cream sauce by gently heating a mixture of heavy cream and whole milk in a saucepan. Gradually melt in shredded cheese, stirring continuously to avoid lumps. Sprinkle in a bit of flour to thicken.
7. Transfer the seasoned mixture into a casserole dish and pour the cream sauce over it evenly, ensuring it covers all ingredients. For extra richness, add a layer of shredded cheese on top.
8. Bake the casserole uncovered in the preheated oven for approximately 1 hour and 20 minutes or until the potatoes are fork-tender. Alternatively, cook in a crockpot on high for 4 hours, checking periodically for doneness.
9. Remove the casserole from the oven or crockpot and allow it to rest for a few minutes.
10. Garnish the casserole with crispy bacon, fried onions, or additional cheese before serving for additional texture and flavor.