Step 1: Brown the Italian Sausage
In a large pot or Dutch oven, heat 1 tablespoon of olive oil over medium heat. Add the Italian sausage, breaking it up with a wooden spoon as it browns. Cook for about 5-7 minutes, or until the sausage is fully cooked and slightly crispy. Use a slotted spoon to transfer the sausage to a plate, leaving the fat in the pot.

Step 2: Sauté the Vegetables
In the same pot with the remaining sausage fat, add the chopped onion and cook for 3-4 minutes until softened. Add the minced garlic and sauté for another 1 minute, until fragrant but not browned.

Step 3: Build the Soup Base
Pour in the chicken broth and the can of diced tomatoes (including the juices). Stir to combine, scraping up any browned bits from the bottom of the pot for extra flavor. Add the dried oregano and season with salt and pepper to taste. Bring the mixture to a simmer.

Step 4: Simmer and Add Cream
Once the soup is simmering, reduce the heat to low and stir in the heavy cream. Let the soup continue to simmer gently for about 10 minutes, allowing the flavors to meld together and the soup to thicken slightly.

Step 5: Add Spinach and Parmesan
Stir in the fresh spinach (or kale if you prefer) and let it wilt into the soup, which will take about 1-2 minutes. Then, add the grated Parmesan cheese, stirring until fully melted and incorporated into the soup. The Parmesan adds a rich, umami flavor that complements the sausage beautifully.

Step 6: Return the Sausage
Return the cooked sausage to the pot and stir everything together. Allow the soup to cook for another 5 minutes to ensure all the flavors are well combined. Taste the soup and adjust the seasoning if necessary, adding more salt, pepper, or crushed red pepper flakes for an extra kick.

Step 7: Garnish and Serve
Once the soup is ready, ladle it into bowls and sprinkle with fresh parsley for a pop of color and added freshness. Serve with crusty bread or garlic bread for dipping, and enjoy!