Preheat a Dutch oven over medium heat. Add olive oil to the pan, add onions and cook until they begin to soften, about 10 minutes. Add garlic and cook for another minute.
Add the tomatoes, chicken stock, salt, pepper, and sugar.
Let the soup simmer for 20 minutes on low heat.
While the soup is simmering, bring a pot of water to a boil and cook the ravioli according to package directions. Drain and set aside. If using fresh, add directly to the soup a few minutes before serving.
Stir in cream and balsamic vinegar. Taste and adjust seasonings as needed.
Puree if desired.
Add basil right before serving. Add cooked ravioli and garnish with Parmesan and extra basil.