Heat Olive oil over medium to low heat in Dutch oven or large pot. Once hot, add onions and season generously with salt. Cook the onions, stirring occasionally, until soft and starting to turn golden brown, about 15 minutes. Add the garlic and cook for 1 more minute, stirring to avoid burning garlic.

Stir in tomatoes and chicken stock. Season generously with salt and pepper. Bring soup to a boil, then lower heat to maintain a simmer for at least 15 minutes.

Purée mixture using an immersion blender or carefully transfer soup to a blender. If using blender return mixture to pot.

Stir in the cream and basil and let it simmer for at least 15 minutes. If desired, you can simmer longer to reduce it down to a thicker consistency.

Serve immediately, topped with Parmesan cheese, a sprinkle of pepper, and a chiffonade of basil.