In a large saucepan or pot heat olive oil over medium high heat. Add in onion and saute until soft and translucent, about 5-7 minutes. Add in garlic and cook 1 minute more.
Add in Italian seasoning, basil, salt, pepper, diced tomatoes, and chicken broth. Bring to a boil reduce heat to medium low, and simmer 5 minutes.
Stir in gnocchi, spinach, heavy cream and grated parmesan (if using.) The residual heat will cook the gnocchi and wilt the spinach.