In a sizeable pot, heat the butter over a medium flame until melted. Stir in the onions and garlic, cooking them until they become clear and fragrant.
Add the diced potatoes to the pot and stir to mix. Pour in the broth, ensuring that the potatoes are fully covered. Bring to a boil.
When the soup reaches a boil, lower the heat and let it simmer with the pot covered. Allow the potatoes to cook until soft, which should take about 15-20 minutes.
With the potatoes tender, add the cream and shredded cheese to the pot. Stir until the cheese has melted and the soup is well mixed.
For a creamier texture, use an immersion blender to blend the soup right in the pot until the desired consistency is reached.
Add the crumbled bacon, season with salt and pepper, and continue to cook for another 5 minutes.
Serve hot, garnished with chopped chives, more crumbled bacon, and a dollop of sour cream if desired.