Rinse the cannellini beans under cold water, remove debris, and soak in a large bowl of water overnight.

Drain the soaked beans and transfer to a pot. Cover with fresh water and bring to a boil for 3-4 minutes, then drain.

Heat olive oil in a large pot, add diced onion and minced garlic, sauté until soft and golden, about 5-7 minutes.

Add drained beans to the pot with water or vegetable stock. Bring to a boil and then reduce to a simmer.

Simmer for about 2 hours, stirring occasionally, until beans are tender and soup has thickened.

Stir in chopped celery and sliced carrot, season with salt and pepper, and cook for an additional 20 minutes.

Before serving, stir in lemon zest and juice, then simmer for an additional 2 minutes.

Ladle soup into bowls and garnish with pepper and lemon juice, serving with crusty bread.