In a large pot, heat over medium-high heat and add the Italian sausage. Cook for 5–7 minutes until browned and fully cooked.

Lower the heat to medium and add unsalted butter. Once melted, add the mirepoix, sautéing for 5–10 minutes until softened. Add minced garlic for an additional 30 seconds.

Stir in chopped baby gold potatoes, dried parsley, basil, salt, and pepper. Pour in chicken stock and bring to a boil, then reduce heat to low and simmer for 15–20 minutes.

In a separate saucepan, melt the remaining butter over medium heat. Whisk in the flour, stirring for about 2 minutes to create a roux. Gradually add in the milk and whisk until thickened, around 5 minutes.

Pour the roux into the soup pot, stirring to combine. Add cheddar cheese and sour cream, mixing until melted and creamy. Return the sautéed sausage to the pot.

Ladle soup into bowls and garnish with fresh herbs. Serve alongside hearty buttered bread.