Heat oil or butter in large pan, then add onion and garlic.
For a meat, chicken or bacon-flavoured soup, add it now, thinly sliced or finely chopped, and cook, stirring, until browned. Add firm vegetables as they take the longest to cook. Cook, stirring, until vegetables are just soft.
Add enough stock to cover the vegetable mixture in pan. Bring the stock to the boil. For a tomato-based soup, add a can of undrained crushed tomatoes.
For a hearty soup, at this stage add either rice, lentils, pearl barley or pasta, if desired. Simmer, uncovered, until grains and vegetables are just tender. Rice, pasta and red lentils take about 10 minutes to cook. Brown lentils and pearl barley will take about 30 minutes to cook.
When grains and vegetables are almost tender, add quick-cooking green vegetables, such as chopped broccoli, spinach, beans, peas, onions, or canned vegetables.
If you prefer a thick, smooth soup, blend or process mixture to the desired consistency. This is best for soups which don't contain pasta or barely. For a thicker soup with chunks of vegetables, blend only half of the soup until smooth.
Return the soup to pan, adjust the consistency with a little water or extra stock, if necessary, and stir until hot. If using canned beans or lentils, drain, rinse, then add them. Stir until hot.
Season soup with salt, pepper and chopped fresh herbs (or a teaspoon of dried) to taste. If soup needs a little more flavour, ingredients such as Worcestershire sauce, soy sauce, chilli sauce, tomato paste, tomato puree or a can of creamed corn are great boosters.
Suitable to freeze.
Suitable to microwave.