In a soup pot over medium heat, cook the bacon until crisp. With a slotted spoon remove the bacon to a paper towel lined plate.
Add the chopped onion and sliced green onions to the bacon fat and cook, stirring occasionally for about 5 minutes. Add the chopped ham and cook until ham is just starting to brown.
Add the potatoes and chicken broth. Bring to a boil and then reduce heat to simmer. Cook until potatoes are very tender. Use a potato masher to roughly mash some of the potatoes.
Stir in about 3/4 of the pimentos, the cheese and sour cream. Stir until cheese is melted and sour cream is dissolved into the soup.
Season with salt and pepper to taste.
Can be kept covered in the refrigerator for 2 days. Gently reheat on the stove top to serve. Top soup with the cooked bacon, reserved pimentos and chopped fresh parsley.