Step 1: Heat the olive oil in a large pot or Dutch oven over medium heat. Add the diced onion and cook until softened and translucent, about 5-7 minutes.
Step 2: Add the minced garlic to the pot and cook for another minute until fragrant, being careful not to burn it.
Step 3: Pour in the crushed tomatoes, chicken or vegetable broth, and Italian seasoning. Stir to combine. Bring the mixture to a gentle simmer.
Step 4: Reduce the heat to low, cover the pot, and let the soup simmer for at least 15-20 minutes to allow the flavors to meld and deepen. Season with salt and pepper to taste.
Step 5: Stir in the heavy cream and 1/2 cup of grated Parmesan cheese. Continue to simmer gently for another 5 minutes, allowing the soup to warm through and the cheese to melt, creating a luscious creamy texture.
Step 6: Carefully add the gnocchi to the simmering soup. Cook according to package directions, typically 2-3 minutes, or until the gnocchi float to the surface and are tender. Avoid overcooking to prevent mushiness.
Step 7: Stir in the fresh spinach, a handful at a time, allowing it to wilt into the hot soup. Once all the spinach is wilted, your creamy tomato and spinach gnocchi soup is ready.
Step 8: Ladle the gnocchi soup into bowls. Garnish with extra grated Parmesan cheese and fresh basil or parsley, if desired. Serve hot with crusty bread.