In a large pot over medium-high heat, add your Italian sausage. Using a wooden spoon, crumble the sausage while it cooks for about 5-7 minutes until it's browned and no longer pink. If there's excess grease, drain it to keep your soup creamy and rich.

In the same pot, toss in the unsalted butter and let it melt over medium heat. Add in the mirepoix and sauté for 3-5 minutes, stirring frequently until softened. Stir in the minced garlic and cook for an additional 30 seconds.

Stir in the chopped baby gold potatoes, dried parsley, basil, salt, and pepper. Pour in the chicken stock, ensuring everything is well mixed. Increase the heat to high and bring the mixture to a boil.

Once boiling, reduce the heat to low, cover the pot, and let it simmer for 15-20 minutes.

In a separate small pot, melt 3 tablespoons of butter over medium heat. Whisk in the flour to create a roux, cooking for about 1-2 minutes. Gradually whisk in the milk until the mixture thickens.

Slowly stir your roux into the vegetable mixture in the large pot, followed by the heavy cream. Add the shredded extra-sharp cheddar cheese and sour cream, stirring until melted and smooth.

Finally, return the browned sausage to the pot, stirring to combine flavors. Adjust seasoning with salt and pepper as needed. Serve warm, ideally alongside hearty buttered bread.