Even the humble lentil requires a little thought in preparation. Do you cook them with flavouring vegetables, or do you add the vegetables at the end? Do you simmer them in plenty of water, or in just as much as they will absorb?
On the first point, I have come round to the view that cooking the vegetables apart is best. I soften diced onion, carrot and celery with chopped garlic in olive oil until they are golden, and tip them into the lentils for just a five-minute merging. Vegetables go null if boiled for too long.
Making a salad, I simmer lentils and drain them. That way, I can make sure that they retain distinct shapes rather than turning to mush, and I can lose as much water as possible before adding oil and vinegar.
Stewing lentils, I prefer the absorption method. Recipe books tend to advise you to cover the lentils with water and simmer them for half an hour, implying that after that time the water will have been absorbed and the lentils will be tender; but of course it never works as neatly as that. You have to tend to them every so often. Rinse them in a sieve, put them in a saucepan, and cover them with water with about 1 cm to spare. Bring to the boil, turn down the flame, and cover the pan. Check after 10 minutes: the water may well have vanished. Pour in just enough more (I use hot water from a kettle, but you could add cold, turning up the heat until the lentils simmer again) to be level with the topmost lentils. Cover the pan again. And so on, until the lentils are tender.
I do as the recipes advise, and wait until this stage to add salt -- my experiments with dried beans suggest that this is a sensible procedure. But I might have flavoured the cooking water with a bay leaf, and/or a whole garlic clove or two, and/or an onion. Now I add the oil-softened vegetables, along with chopped parsley if I have it, and a good deal of pepper. I allow the ingredients to get to know each other -- Fergus Henderson's phrase -- for five minutes longer.
I am talking here about green (Puy, if you're lucky) lentils, or brown ones. The grey/brown ones are less interesting. Red ones, which soon go mushy, are best for dhals and soups.
The other day, I cooked the lentils in advance. They carried on absorbing liquid as they cooled. By the time I warmed them up again, they had a perfect consistency.