Cook bacon in a Dutch oven or soup pot until crisp and browned, then remove the bacon and set it aside, leaving the rendered fat in the pot.

Add butter and chopped onion to the pot and cook over medium heat until the onions are tender, which takes about 3-5 minutes.

Stir in minced garlic and cook for approximately 30 seconds until it becomes fragrant.

Sprinkle all-purpose flour over the ingredients in the pot and stir until the mixture is smooth, using a whisk if needed.

Add the diced gold potatoes, chicken broth, milk, heavy cream, salt, pepper, and ancho chili powder to the pot and stir everything together thoroughly.

Bring the mixture to a boil and cook for about 10 minutes, or until the potatoes are tender when pierced with a fork.

Reduce the heat to a simmer, then carefully remove about half of the soup (approximately 5 cups) to a blender and puree until smooth; alternatively, use an immersion blender directly in the pot.

Return the pureed soup to the pot, then add the sour cream and the reserved cooked bacon pieces, stirring well to combine.

Allow the soup to simmer for 15 minutes before serving, then top with additional sour cream, bacon, shredded cheddar cheese, or chives if desired.