Brown the Sausage: In a large pot, heat the olive oil and 2 tablespoons of butter over medium heat. Add the Italian sausage and cook until browned, about 5-7 minutes. Remove and set aside.
Sauté the Veggies: In the same pot, add the mirepoix and minced garlic. Sauté until softened and fragrant, approximately 4-5 minutes.
Add the Potatoes and Stock: Stir in the chopped baby gold potatoes, dried parsley, dried basil, chicken stock, salt, and pepper. Bring to a boil, then reduce heat and simmer until the potatoes are tender, about 15-20 minutes.
Thicken the Soup: In a separate bowl, combine the flour and milk, whisking until smooth. Gradually add this mixture to the pot, stirring constantly until thickened, about 2-3 minutes.
Make it Creamy: Stir in the heavy cream, remaining butter, cooked sausage, freshly shredded Cheddar cheese, and sour cream. Heat until melted and heated through, about 3-4 minutes.
Serve and Enjoy: Ladle the soup into bowls and serve with hearty buttered bread.
