Instructions:
- Heat olive oil in a large Dutch oven or heavy-bottomed pot over medium heat. Add onion, carrots, and celery. Sauté for 8–10 minutes until softened (sweating, not browning).
- Stir in the minced garlic and tomato paste. Cook for 1 minute until the paste darkens slightly.
- Pour in a splash of broth, scraping up any browned bits from the bottom of the pot. Add the remaining broth, canned tomatoes (crushing them slightly by hand), oregano, basil, and bay leaf.
- Bring the mixture to a gentle boil, then reduce heat to low, cover partially, and simmer for 30 minutes to let the flavours meld.
- While simmering, rinse and drain the cannellini beans. In a blender, combine the drained beans with 1 cup of the hot tomato liquid (ensure the bay leaf has been removed). Blend until perfectly smooth and creamy.
- Pour the smooth bean mixture back into the pot. Carefully transfer the entire soup mixture to the blender (or use an immersion blender) and blend until completely smooth.
- Stir in the Greek yogurt until fully incorporated. Heat through gently over low heat (do not boil after adding yogurt).
- Taste and adjust seasoning with salt, pepper, and the optional teaspoon of sugar to balance the acidity. Ladle hot into bowls immediately.