Chop vegetables into the same size. Heat up a soup pot and add oil.
Start with onions and some salt. Saute for ≈3 minutes. Add the rest of the ingredients. Remember to salt.
Pour enough water or broth to cover ingredients.
Cover and bring to a boil, then simmer for 15-20 minutes. Remove lid and let it cool for a bit.
Puree with an immersion blender. Don't forget to season to taste.