Heat olive oil in a 5-quart Dutch oven or heavy soup pot over medium heat. Add chopped yellow onion and cook for 5 to 6 minutes until soft, translucent, and sweet.

Add minced garlic and tomato paste. Cook, stirring constantly, for 2 minutes until the tomato paste darkens into a deep mahogany color and the garlic is fragrant.

Pour in crushed San Marzano tomatoes, vegetable broth, Italian seasoning, sugar, red pepper flakes, salt, and black pepper. Stir well, scraping up any fond from the bottom of the pot.

Bring the soup to a gentle boil, then lower the heat to medium-low and simmer uncovered for 10 minutes to allow the flavors to deepen and harmonize.

Add the refrigerated cheese tortellini to the simmering broth. Cook for 3 to 4 minutes just until the tortellini float to the top and are tender al dente (do not overcook).

Reduce heat to low. Stir in heavy cream, grated Parmesan cheese, and fresh ribboned basil. Simmer for 1 to 2 minutes until the soup is silky, velvety, and warmed through. Ladle into bowls and serve with toasted artisan garlic bread!