Prep Ingredients: Wash and peel the potatoes, then cut them into bite-sized cubes. In a large mixing bowl, combine cubed potatoes with chopped cooked ham, shredded cheddar cheese, and diced onion.

Mix Sauces: In a separate bowl, whisk together sour cream, cream of mushroom soup, milk, minced garlic, salt, black pepper, and dried thyme until smooth and well blended.

Combine Mixtures: Pour the creamy soup mixture over the potato and ham mixture. Gently fold together to ensure everything is coated evenly.

Transfer to Slow Cooker: Lightly grease the inside of the slow cooker. Pour the mixture into the slow cooker, leveling it out with a spatula.

Cook: Cover and set to cook on low for 6 to 8 hours until potatoes are fork-tender and casserole is bubbling.

Garnish & Serve: Open the lid, stir gently, and sprinkle with freshly chopped parsley before serving.