Grease or spray crock.
Add potatoes, 2 cups of cheese and onion to slow cooker.
In a medium bowl, whisk together soup melted butter, sour cream, onion powder, garlic powder, paprika, salt and pepper until blended.
Add mixture to slow cooker and stir to combine.
Cook on low for 3 hours and 45 minutes.
Remove lid and stir potatoes.
Add remaining cheese.
Place paper towel across top of slow cooker and replace lid.
Cook on low for an additional 30 minutes.