Greek White Bean Soup With Garlic & Lemon

Name: Greek White Bean Soup With Garlic & Lemon
Cook time: 2 h
Total time: 2 h
Cuisine: Greek
Ingredients: 250 grams / 8.8 oz cannellini beans (or other small white beans) (soaked in water overnight); 6 tablespoons olive oil (extra virgin); 1/2 onion (minced); 3 garlic cloves (chopped); 1 carrot (cut into very thin slices); 1 stick of celery (finely chopped); 1 lemon zest + juice; kosher salt + freshly ground pepper; OPTIONAL: 500 ml vegetable stock