For the potatoes, if using frozen, thaw first. If using fresh, peel, then dice to about ½ inch cubes. Add potatoes to the slow cooker. In Thailand, Makro has frozen cubed potatoes 15x15mm. I dice fresh by cutting first with a French fry cutter then use a knife to cut the cubes.
Add sausage, onion, garlic powder, and 2 cups of the cheese to your slow cooker. In Thailand I use what is called Sausage Scraps from Makro, excellent sausage, 4 types in one package, one type is very much like kielbasa.
Mix together.
Add the soup to the slow cooker and mix into the potato mixture.
Cover and set to Low and cook for 3 to 4 hours. Check at 3 hours for fork tender potatoes. If not tender, check again at 3½ hours to 4 hours.
When potatoes are tender, add the sour cream and stir in.
Top with the remaining 1 cup of cheese, cover and continue cooking. If you like cheese, feel free to add more on the top.
When the cheese is melted, the casserole is ready.
Serve and enjoy.