In a large soup pot add 1/2 the oil, sweat onions until tender.
Add garlic, basil, black pepper, remaining oil and flour to form roux.
Add 1/2 of the veggie stock, stir continuously to make veloute.
Assembly
When veloute thickens (approx. 1 hour), add tomatoes, tomato paste. Cook for 20 minutes. Adjust consistency with remaining stock.
Add sour cream, stir and lower heat to holding temperature.
Season with salt.
Finish
Serve over cheese ravioli or pasta and garnish with parsley.