Preheat oven to 450°F. Cut the top off the garlic head to expose the cloves. Place in a muffin tin, drizzle with olive oil, and cover loosely with foil. Roast for 45 minutes, or until softened and fragrant. Let cool, then squeeze out the roasted garlic cloves.

In a large pot or Dutch oven, brown the Italian sausage over medium heat. Remove sausage and set aside. Drain off excess grease, leaving about 1 tablespoon.

Add onion, carrots, and celery to the pot and cook until softened, about 7-8 minutes. Add chicken broth and chopped potatoes. Season with Italian seasoning, salt, and pepper. Bring to a boil, then reduce heat and simmer for 20 minutes, or until potatoes are tender.

Add the roasted garlic to the pot. Use an immersion blender (or transfer to a regular blender) to partially blend the soup, leaving some chunks of potato and vegetables.

Return the cooked sausage to the pot. Stir in the half and half and kale. Cook until the kale is wilted, about 6 minutes. Adjust seasoning to taste.

Serve immediately, garnished with fresh parsley.