Coarsely chop onion, mushrooms, celery, and carrots. Add to food processor. Add garlic cloves to processor. Pulse until finely diced.
Heat olive oil over medium heat in a 5.5 qt pot. Add processed vegetables to the pot. Stir and turn heat down to medium-low.
Core tomatoes, coarsely chop, and process in batches until pureed in food processor. With last batch, add basil leaves. Add each batch to pot and stir. Once all tomatoes and basil are added stir well to blend, and turn heat up to medium again.
Stir in salt, pepper, Italian seasoning, crushed red pepper, garlic powder, balsamic vinegar, and red wine, if using. Cover and bring to a simmer, stirring frequently. Once simmering, turn down heat to keep at a simmer. Add parmesan rind, if using. Simmer uncovered 30 minutes, stirring often.
Whisk in spelt flour. Add cream and grated parmesan, if using. Simmer 1 more minute to cook flour.