In a large pot or Dutch oven, heat olive oil over medium heat. Sauté diced carrots, celery, and onion until softened, about 5-7 minutes. Add minced garlic and cook for another minute until fragrant.

Stir in the rinsed and drained cannellini beans, vegetable broth, and diced tomatoes. Bring the mixture to a boil, then reduce heat and simmer for 30 minutes, allowing the flavors to meld.

Season with salt and pepper to taste. For a thicker consistency, you can mash a portion of the beans against the side of the pot. Serve hot, garnished with fresh parsley if desired.