In a large pot or Dutch oven, cook the Italian sausage over medium heat, breaking it up into smaller pieces with a spoon, until browned and cooked through. Remove the sausage from the pot and set aside.

In the same pot, add the diced onion and minced garlic. Cook until the onion is softened and translucent, about 3-4 minutes.

Add the diced tomatoes (with their juices) to the pot, along with the chicken or vegetable broth, dried basil, and dried oregano. Stir to combine.

Bring the mixture to a simmer, then add the uncooked orzo pasta. Cook for about 8-10 minutes, or until the orzo is tender.

Once the orzo is cooked, return the cooked Italian sausage to the pot. Stir in the chopped spinach and cook for an additional 2-3 minutes, until the spinach is wilted.

Season the soup with salt and pepper to taste.

Serve the soup hot, garnished with grated Parmesan cheese and fresh basil leaves, if desired.

Enjoy your delicious Italian sausage tomato orzo soup! Feel free to customize it with additional vegetables or spices to suit your taste preferences.