Saute onion and garlic in butter in a large soup pot until onions are soft
Add chicken broth, thyme, salt and potatoes to onion and garlic
Simmer over medium to medium/high heat for 30-40 minutes stirring frequently, until potatoes are soft
Remove soup from heat
Mash some potatoes with a potato masher, leaving some diced: to the consistency that you desire
Add sour cream and heavy whipping cream to the soup, stirring to combine
Add shredded cheese 1/4 cup at a time stirring constantly
Serve with bacon, green onions and/or shredded cheese on top
Notes
Do not bring the soup back to a boil after adding dairy
Add shredded cheese slowly, or it will clump
For reheating: add chicken broth, water or milk to thin out