In a large pot or Dutch oven, heat the olive oil over medium heat. Add the diced onion, garlic, carrots, and celery. Sauté for about 5 minutes, stirring occasionally, until the vegetables soften and the onions turn translucent. The aroma should be fragrant but not browned.

Sprinkle in the oregano, basil, red pepper flakes (if using), salt, and black pepper. Stir everything together, allowing the spices to bloom for about 30 seconds. Then pour in the chicken broth and diced tomatoes (with their juices). Give it a good stir to combine all the flavors. Taste at this point and adjust salt if needed.

Once the broth starts to simmer, add the drained cannellini beans and the cooked, shredded chicken. Let everything cook together for about 10 minutes so the flavors meld and the chicken absorbs the seasoning. The broth should start to take on a rich, savory color.

Stir in the small pasta and let it cook directly in the broth until al dente, about 8–10 minutes depending on the pasta size. Check for doneness after 7 minutes to avoid overcooking. If the soup starts to thicken too much, add a bit more broth or water to reach your desired consistency. Once the pasta is nearly done, stir in the chopped kale or spinach and let it wilt into the soup, which should take about 1-2 minutes.

Remove the soup from the heat and stir in ¼ cup of grated Parmesan cheese. The cheese will melt into the broth, adding a subtle richness. Ladle the soup into bowls and garnish with fresh parsley and extra Parmesan. Serve hot with crusty bread for dipping.