Vegetable soup with cassava Fariña

Name: Vegetable soup with cassava Fariña
Ingredients: 1 small onion, finely diced; 1 clove of garlic, chopped; 1 green onion, chopped finely; 400 g vegetables of choice, cleaned and diced finely (peas, corn, carrot, fresh or canned beans); 1/2 green plantain, sliced and halved; 2 potatoes, peeled, sliced and halved; 1.5-2 l water; 2 sprigs of cilantro, plus more for serving; 3 bay leafs; salt and pepper; vegetable oil; 1 tbsp vinegar; fariña, to liking (couple of tablespoons); 1 cube of vegetable stock (optional)