In a large pot or Dutch oven, crumble the Italian sausage and cook over medium heat until browned and fully cooked, about 8–10 minutes. Use a wooden spoon to break the sausage into small pieces as it cooks.

Add the chopped onion to the pot and sauté for 3–4 minutes, or until softened and translucent. Stir in the minced garlic and cook for an additional 1 minute, just until fragrant.

Add the diced potatoes and sliced carrots to the pot, stirring to combine with the sausage and aromatics. Pour in the chicken broth, ensuring all the ingredients are submerged. Bring the mixture to a boil, then reduce the heat to medium-low and let it simmer.

Let the soup simmer uncovered for 15–20 minutes, or until the potatoes and carrots are tender. Stir occasionally to prevent sticking and ensure even cooking.

Once the potatoes and carrots are tender, stir in the chopped spinach. Cook for an additional 2–3 minutes, or until the spinach is wilted and vibrant green.

Taste the soup and adjust the seasoning with salt and pepper as needed. Ladle the soup into bowls and serve hot. Garnish with grated Parmesan cheese or fresh herbs like parsley, if desired.