Brown the Sausage: In a large pot over medium heat, cook the Italian sausage, breaking it into crumbles until browned and cooked through. Remove the sausage with a slotted spoon and set aside, leaving the drippings in the pot.

Sauté the Aromatics: In the same pot, add the diced onion and cook until translucent, about 3-5 minutes. Add the minced garlic and cook for an additional 30 seconds until fragrant.

Cook the Potatoes: Pour in the chicken broth and add the diced potatoes. Bring the mixture to a boil, then reduce the heat and let it simmer until the potatoes are fork-tender, approximately 10-12 minutes.

Mash and Thicken: Carefully remove about half of the cooked potatoes and mash them in a bowl. Return the mashed potatoes to the pot, stirring to thicken the soup naturally.

Combine Remaining Ingredients: Return the browned sausage to the pot. Stir in the chopped kale or spinach and the heavy cream. Let the soup simmer for an additional 5 minutes until the greens are wilted and the soup is heated through. Season with salt and pepper to taste.

Serve: Ladle the soup into bowls, garnish with grated Parmesan cheese, and drizzle with a bit of olive oil if desired. Serve hot and enjoy!