Heat the extra virgin olive oil over medium heat in a large pot or Dutch oven. Add the finely diced sweet onion along with a small pinch of salt and black pepper. Cook, stirring often, until the onion softens and turns translucent (about 5 minutes). Stir in the minced garlic and cook for 1 additional minute until fragrant.

Add the tomato paste, dried basil, dried oregano, and dried thyme to the center of the pot. Cook for 2 to 3 minutes, stirring constantly, until the paste darkens to a brick-red color and the herbs release their aromas.

Pour in the fire-roasted diced tomatoes (with their juices), the rinsed cannellini beans, and the chicken or vegetable stock. Drop in the Parmesan rind. Bring the mixture to a boil, then immediately reduce the heat to medium-low. Cover with a lid and let it simmer for 20 minutes.

Remove the lid and carefully discard the Parmesan rind. Lower the stovetop heat to low. Slowly stir in the heavy cream (or Greek yogurt) and the finely grated Parmesan cheese, mixing continuously until the cheese is completely melted and the broth is silky smooth.

Stir the fresh baby spinach leaves directly into the hot liquid. Cook for 2 to 3 minutes, stirring gently, until the leaves are completely wilted. Taste the broth and adjust with extra salt, black pepper, or red pepper flakes to preference.

Ladle the hot soup into bowls. Garnish generously with an extra sprinkle of grated Parmesan cheese and freshly cracked black pepper. Serve alongside a warm slice of crusty sourdough bread.