Heat oil in in a large saucepan and gently cook the onions for 6-8 minutes, or until soft, stirring regularly. Add chopped vegetables and cook for 5 minutes, stirring regularly. Stir in garlic, and continue to cook for 1 minute, or until fragrant. Crumble over stock cubes, add water, and bring mix to a boil. Reduce to simmer, loosely cover with a lid, and cook for 20 minutes or until vegetables are soft. Blend, add salt and pepper to taste, and enjoy as is or with parsley as a garnish.