Heat a large pot over medium-high heat. Add sausage and let it sear for about a minute before using a wooden spoon to crumble it up. Cook until it's deeply browned. Transfer the sausage to a plate lined with paper towels, leaving about one tablespoon of grease in the pot; add olive oil if necessary.

In the same pot, melt one tablespoon of butter. Add diced carrots, celery, and onions. Sauté for about five to seven minutes until softened. Toss in minced garlic and cook for another thirty seconds.

Stir in chopped baby gold potatoes, dried basil, dried parsley, salt, and pepper. Pour in chicken stock and bring to a boil. Reduce heat to medium-low, cover, and cook for about fifteen to twenty minutes until potatoes are fork-tender.

Melt four tablespoons of butter in another pot over medium heat. Whisk in flour for about one minute. Gradually pour in milk while whisking until smooth. Cook while whisking until it thickens slightly and gently boils. Stir in heavy cream before removing from heat.

Once veggies are tender, stir in the creamy mixture into the pot. Turn off the heat and slowly add shredded cheese while stirring until melted. Mix in sour cream and return cooked sausage to the pot. Adjust seasoning with salt and pepper if needed.

Ladle the soup into bowls while warm. Serve with hearty buttered bread if desired.