In a large pot, heat the olive oil or butter over medium heat. Add the diced onion and cook until translucent, about 5 minutes.

Stir in the minced garlic and cook for an additional 1-2 minutes until fragrant.

Add the diced potatoes to the pot and pour in the chicken or vegetable broth. Bring the mixture to a boil, then reduce the heat and let simmer for 15-20 minutes, or until the potatoes are tender.

Once the potatoes are tender, use an immersion blender to blend the soup until smooth. Alternatively, you can transfer the soup in batches to a blender, then return it to the pot.

Stir in the heavy cream, shredded cheddar cheese, and crumbled bacon. Mix well until the cheese is melted and the soup is creamy.

Add salt and pepper to taste. If the soup is too thick, you can add more broth or water to reach your desired consistency.

Serve hot in bowls, topped with additional cheddar cheese, crumbled bacon, a dollop of sour cream, and sliced green onions for garnish.