Heat a stockpot or Dutch oven over medium-high heat. Add the Italian sausage and cook, stirring and chopping until crumbled and browned. Transfer to a plate, leaving 1 tablespoon of grease in the pot. If there's not enough grease, add 1 tablespoon of olive oil.

In the same pot, with the retained grease or olive oil, melt 1 tablespoon of ghee. Add the carrots, celery, and onion. Sauté for 5-7 minutes until softened and aromatic. Stir in the minced garlic and cook for an additional 30 seconds.

Stir in the chopped potatoes, basil, parsley, salt, and black pepper. Add the second tablespoon of ghee, mixing well. Pour in the broth and bring to a boil over medium-high heat. Once boiling, reduce heat to medium, cover, and simmer for 15-20 minutes until the potatoes are fork-tender.

In a separate pot, boil the diced white sweet potato in 2 cups of water until fork-tender, about 10-12 minutes. Drain and transfer to a blender with 2/3 cup of water and 1/4 cup of coconut yogurt. Blend until smooth, adding more water as needed to achieve a creamy consistency.

Pour the cream sauce into the soup, stirring to combine. Reduce heat to low, return the sausage to the pot, and stir for about 30 seconds to meld flavors. Season with additional salt and pepper, garnish with chopped parsley, and serve hot.