How to make vegetable broth? Simple! To make the base you need 4 ingredients:
1 onion, or a small piece of leek, or 2 shallots
1 clove of garlic
1 stick of celery
To this add 1 bay leaf, a few grains of black pepper, a tablespoon of coarse salt and cook in 2 liters of cold water. When it reaches a boil, continue cooking for 20 'and then you can turn it off. Once it was boiled for a long time, but in this way all the nutritional properties are lost.
To this base you can add other ingredients that will characterize your broth depending on whether you want it more full-bodied (1 potato), tastier (3-4 dried mushrooms), more colorful (turmeric, or saffron for the yellow; red turnip for the pink /Violet; spirulina for green).